diff --git a/chunky/src/java/se/llbit/chunky/map/MapTile.java b/chunky/src/java/se/llbit/chunky/map/MapTile.java
index 2f00a9991a..184536f8e5 100644
--- a/chunky/src/java/se/llbit/chunky/map/MapTile.java
+++ b/chunky/src/java/se/llbit/chunky/map/MapTile.java
@@ -71,8 +71,9 @@ public void draw(MapBuffer buffer, WorldMapLoader mapLoader, ChunkView view,
       }
     } else {
       RegionPosition regionPos = new RegionPosition(pos.x, pos.z); // intentionally don't convert, this position represented a region already.
-      boolean isValid = mapLoader.getWorld().currentDimension().regionExistsWithinRange(regionPos, view.yMin, view.yMax);
-      Region region = mapLoader.getWorld().currentDimension().getRegionWithinRange(regionPos, view.yMin, view.yMax);
+      HeightRange heightRange = new HeightRange(view.yMin, view.yMax);
+      boolean isValid = mapLoader.getWorld().currentDimension().hasRegionWithinRange(regionPos, heightRange);
+      Region region = mapLoader.getWorld().currentDimension().getRegionWithinRange(regionPos, heightRange);
       int pixelOffset = 0;
       for (int z = 0; z < 32; ++z) {
         for (int x = 0; x < 32; ++x) {
diff --git a/chunky/src/java/se/llbit/chunky/map/WorldMapLoader.java b/chunky/src/java/se/llbit/chunky/map/WorldMapLoader.java
index 1119340ea5..93b0c915cf 100644
--- a/chunky/src/java/se/llbit/chunky/map/WorldMapLoader.java
+++ b/chunky/src/java/se/llbit/chunky/map/WorldMapLoader.java
@@ -16,15 +16,20 @@
  */
 package se.llbit.chunky.map;
 
+import java.util.Optional;
 import java.util.function.BiConsumer;
 import se.llbit.chunky.PersistentSettings;
 import se.llbit.chunky.renderer.ChunkViewListener;
 import se.llbit.chunky.ui.controller.ChunkyFxController;
 import se.llbit.chunky.world.*;
+import se.llbit.chunky.world.java.JavaWorldFormat;
 import se.llbit.chunky.world.region.RegionChangeWatcher;
 import se.llbit.chunky.world.region.RegionParser;
 import se.llbit.chunky.world.region.RegionQueue;
 import se.llbit.chunky.world.listeners.ChunkTopographyListener;
+import se.llbit.chunky.world.worldformat.WorldFormats;
+import se.llbit.log.Log;
+import se.llbit.util.annotation.Nullable;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -64,28 +69,75 @@ public WorldMapLoader(ChunkyFxController controller, MapView mapView) {
     topographyUpdater.start();
   }
 
+  public void loadWorldFromDirectory(@Nullable File worldLocation, @Nullable String worldFormatId) {
+    if (worldLocation != null) {
+      if (worldFormatId == null || worldFormatId.isEmpty()) {
+        worldFormatId = JavaWorldFormat.ID;
+      }
+      Optional<World.Info> info = WorldFormats.getWorldFormat(worldFormatId)
+        .flatMap(format -> format.getWorldInfo(worldLocation.toPath())) // attempt to get the given format
+        .or(() -> WorldFormats.getInfos(worldLocation.toPath()).stream().findFirst()); // get any format
+      info.ifPresent(this::loadWorld);
+      return;
+    }
+    setWorld(EmptyWorld.INSTANCE);
+  }
+
   /**
-   * This is called when a new world is loaded
+   * Load the world referred to by the {@link World.Info}
+   *
+   * @return The loaded world. May be {@link EmptyWorld} if loading failed.
    */
-  public void loadWorld(File worldDir) {
-    if (World.isWorldDir(worldDir)) {
-      if (world != null) {
-        world.currentDimension().removeChunkTopographyListener(this);
-      }
-      boolean isSameWorld = !(world instanceof EmptyWorld) && worldDir.equals(world.getWorldDirectory());
-      World newWorld = World.loadWorld(worldDir, currentDimensionId, World.LoggedWarnings.NORMAL);
-      newWorld.currentDimension().addChunkTopographyListener(this);
-      synchronized (this) {
-        world = newWorld;
-        updateRegionChangeWatcher(newWorld.currentDimension());
-
-        File newWorldDir = world.getWorldDirectory();
-        if (newWorldDir != null && !newWorldDir.equals(PersistentSettings.getLastWorld())) {
-          PersistentSettings.setLastWorld(newWorldDir);
-        }
+  public World loadWorld(World.Info info) {
+    World newWorld = WorldFormats.createWorld(info);
+
+    Optional<Dimension.Identifier> dimensionToLoad = Optional.of(world.currentDimension())
+      .map(Dimension::getDimensionId)
+      .filter(dimension -> newWorld.getAvailableDimensions().contains(dimension))
+      .or(newWorld::getDefaultDimension)
+      .or(() -> newWorld.getAvailableDimensions().stream().findFirst());
+
+    if (dimensionToLoad.isPresent()) {
+      newWorld.loadDimension(dimensionToLoad.get());
+    } else {
+      Log.infof("No dimension loaded for world %s", info.toString());
+    }
+
+    setWorld(newWorld);
+    return this.world;
+  }
+
+  /**
+   * Sets the map view world.
+   * <p>This is intended to be called with worlds with a dimension already loaded, as it will not trigger dimension
+   * loading.</p>
+   *
+   * @param newWorld The world to set
+   */
+  public void setWorld(World newWorld) {
+    if (this.world != null) {
+      this.world.currentDimension().removeChunkTopographyListener(this);
+    }
+
+    boolean isSameWorld = !(this.world instanceof EmptyWorld) && newWorld.getInfo().path().equals(this.world.getInfo().path());
+
+    Dimension loadedDim = newWorld.currentDimension();
+    if (loadedDim == EmptyWorld.INSTANCE.currentDimension()) {
+      Log.warn("Map view world was set but it has no dimension!");
+    }
+
+    loadedDim.addChunkTopographyListener(this);
+    synchronized (this) {
+      this.world = newWorld;
+      updateRegionChangeWatcher(loadedDim);
+
+      File newWorldDir = this.world.getInfo().path().toFile();
+      if (!newWorldDir.equals(PersistentSettings.getLastWorld())) {
+        PersistentSettings.setLastWorld(newWorldDir);
       }
-      worldLoadListeners.forEach(listener -> listener.accept(newWorld, isSameWorld));
+      PersistentSettings.setLastWorldFormat(newWorld.getInfo().worldFormat().getId());
     }
+    worldLoadListeners.forEach(listener -> listener.accept(newWorld, isSameWorld));
   }
 
   /**
@@ -151,14 +203,12 @@ public void regionUpdated(RegionPosition region) {
   public void reloadWorld() {
     topographyUpdater.clearQueue();
     world.currentDimension().removeChunkTopographyListener(this);
-    World newWorld = World.loadWorld(world.getWorldDirectory(), currentDimensionId,
-        World.LoggedWarnings.NORMAL);
-    newWorld.currentDimension().addChunkTopographyListener(this);
+    world.loadDimension(currentDimensionId);
+    world.currentDimension().addChunkTopographyListener(this);
     synchronized (this) {
-      world = newWorld;
-      updateRegionChangeWatcher(newWorld.currentDimension());
+      updateRegionChangeWatcher(world.currentDimension());
     }
-    worldLoadListeners.forEach(listener -> listener.accept(newWorld, true));
+    worldLoadListeners.forEach(listener -> listener.accept(world, true));
     viewUpdated(mapView.getMapView()); // update visible chunks immediately
   }
 
@@ -173,6 +223,8 @@ private void updateRegionChangeWatcher(Dimension dimension) {
 
   /**
    * Set the current dimension.
+   *
+   * @param value Must be a valid dimension see {@link World#getAvailableDimensions()}
    */
   public void setDimension(Dimension.Identifier value) {
     if (value != currentDimensionId) {
diff --git a/chunky/src/java/se/llbit/chunky/renderer/scene/Scene.java b/chunky/src/java/se/llbit/chunky/renderer/scene/Scene.java
index bc4bc6bf61..c4b923dffc 100644
--- a/chunky/src/java/se/llbit/chunky/renderer/scene/Scene.java
+++ b/chunky/src/java/se/llbit/chunky/renderer/scene/Scene.java
@@ -53,7 +53,9 @@
 import se.llbit.chunky.world.biome.Biome;
 import se.llbit.chunky.world.biome.BiomePalette;
 import se.llbit.chunky.world.biome.Biomes;
-import se.llbit.chunky.world.region.MCRegion;
+import se.llbit.chunky.world.java.JavaWorldFormat;
+import se.llbit.chunky.world.region.Region;
+import se.llbit.chunky.world.worldformat.WorldFormats;
 import se.llbit.json.*;
 import se.llbit.log.Log;
 import se.llbit.math.*;
@@ -67,6 +69,7 @@
 import se.llbit.util.mojangapi.MinecraftProfile;
 
 import java.io.*;
+import java.nio.file.Path;
 import java.text.SimpleDateFormat;
 import java.util.*;
 import java.util.concurrent.ExecutionException;
@@ -192,6 +195,7 @@ public class Scene implements JsonSerializable {
    */
   protected int rayDepth = PersistentSettings.getRayDepthDefault();
   protected String worldPath = "";
+  protected String worldFormat = JavaWorldFormat.ID;
   protected Dimension.Identifier worldDimension = Dimension.Identifier.OVERWORLD;
   protected RenderMode mode = RenderMode.PREVIEW;
   protected int dumpFrequency = DEFAULT_DUMP_FREQUENCY;
@@ -404,6 +408,7 @@ public synchronized void copyState(Scene other, boolean copyChunks) {
     if (copyChunks) {
       loadedWorld = other.loadedWorld;
       worldPath = other.worldPath;
+      worldFormat = other.worldFormat;
       worldDimension = other.worldDimension;
 
       // The octree reference is overwritten to save time.
@@ -546,11 +551,17 @@ public synchronized void loadScene(RenderContext context, String sceneName, Task
 
       loadedWorld = EmptyWorld.INSTANCE;
       if (!worldPath.isEmpty()) {
-        File worldDirectory = new File(worldPath);
-        if (World.isWorldDir(worldDirectory)) {
-          loadedWorld = World.loadWorld(worldDirectory, worldDimension, World.LoggedWarnings.NORMAL);
-        } else {
-          Log.info("Could not load world: " + worldPath);
+        Path worldDirectory = Path.of(worldPath);
+        Optional<World.Info> info = WorldFormats.getWorldFormat(worldFormat) // only try to load the world as its known world format.
+          .flatMap(format -> format.getWorldInfo(worldDirectory));
+
+        if (info.isPresent()) {
+          World newWorld = WorldFormats.createWorld(info.get());
+          loadedWorld = newWorld;
+          loadedWorld.loadDimension(this.worldDimension);
+          if (newWorld == EmptyWorld.INSTANCE) {
+            Log.info("Could not load world: " + worldPath);
+          }
         }
       }
 
@@ -767,7 +778,7 @@ public synchronized void reloadChunks(TaskTracker taskTracker) {
       Log.warn("Can not reload chunks for scene - world directory not found!");
       return;
     }
-    loadedWorld = World.loadWorld(loadedWorld.getWorldDirectory(), worldDimension, World.LoggedWarnings.NORMAL);
+    loadedWorld.loadDimension(worldDimension);
     loadChunks(taskTracker, loadedWorld, ChunkSelectionTracker.selectionByRegion(chunks));
     refresh();
   }
@@ -803,7 +814,8 @@ public synchronized void loadChunks(TaskTracker taskTracker, World world, Map<Re
       task.update(2, 1);
 
       loadedWorld = world;
-      worldPath = loadedWorld.getWorldDirectory().getAbsolutePath();
+      worldPath = loadedWorld.getInfo().path().toAbsolutePath().toString();
+      worldFormat = world.getInfo().worldFormat().getId();
       worldDimension = world.currentDimension().getDimensionId();
 
       if (chunksToLoadByRegion.isEmpty()) {
@@ -860,8 +872,8 @@ public synchronized void loadChunks(TaskTracker taskTracker, World world, Map<Re
 
       ExecutorService executor = Executors.newSingleThreadExecutor();
 
-      ChunkData[] regionParsingDataArray = new ChunkData[MCRegion.CHUNKS_X * MCRegion.CHUNKS_Z];
-      ChunkData[] chunkLoadingDataArray = new ChunkData[MCRegion.CHUNKS_X * MCRegion.CHUNKS_Z];
+      ChunkData[] regionParsingDataArray = new ChunkData[Region.CHUNKS_X * Region.CHUNKS_Z];
+      ChunkData[] chunkLoadingDataArray = new ChunkData[Region.CHUNKS_X * Region.CHUNKS_Z];
 
       BiFunction<RegionPosition, ChunkData[], Future<List<ObjectObjectImmutablePair<ChunkPosition, ChunkData>>>> createRegionDataFuture = (regionPosition, chunkDataArray) -> executor.submit(() -> {
         List<ChunkPosition> chunkPositionsToLoad = chunksToLoadByRegion.get(regionPosition);
@@ -2670,6 +2682,7 @@ public void setUseCustomWaterColor(boolean value) {
       // Save world info.
       JsonObject world = new JsonObject();
       world.add("path", worldPath);
+      world.add("worldType", loadedWorld.getInfo().worldFormat().getId());
       world.add("dimension", worldDimension.getNamespacedName());
       json.add("world", world);
     }
@@ -2992,7 +3005,7 @@ else if(waterShader.equals("SIMPLEX"))
     if (json.get("world").isObject()) {
       JsonObject world = json.get("world").object();
       worldPath = world.get("path").stringValue(worldPath);
-
+      worldFormat = world.get("worldFormat").stringValue(JavaWorldFormat.ID);
       if (world.get("dimension") instanceof JsonString) {
         // dimension already is a string (or undefined)
         worldDimension = Dimension.Identifier.fromNamespacedName(world.get("dimension").stringValue("minecraft:overworld"));
diff --git a/chunky/src/java/se/llbit/chunky/ui/ChunkMap.java b/chunky/src/java/se/llbit/chunky/ui/ChunkMap.java
index 270374e554..7619c60f3f 100644
--- a/chunky/src/java/se/llbit/chunky/ui/ChunkMap.java
+++ b/chunky/src/java/se/llbit/chunky/ui/ChunkMap.java
@@ -19,22 +19,16 @@
 
 import javafx.application.Platform;
 import javafx.geometry.Point2D;
-import javafx.geometry.Pos;
 import javafx.scene.Scene;
 import javafx.scene.canvas.Canvas;
 import javafx.scene.canvas.GraphicsContext;
 import javafx.scene.control.*;
-import javafx.scene.control.Button;
-import javafx.scene.control.Dialog;
 import javafx.scene.control.MenuItem;
-import javafx.scene.image.Image;
 import javafx.scene.image.ImageView;
 import javafx.scene.input.KeyEvent;
 import javafx.scene.input.MouseButton;
 import javafx.scene.input.MouseEvent;
 import javafx.scene.input.ScrollEvent;
-import javafx.scene.layout.Border;
-import javafx.scene.layout.GridPane;
 import javafx.stage.PopupWindow;
 import se.llbit.chunky.map.MapBuffer;
 import se.llbit.chunky.map.MapView;
@@ -45,11 +39,10 @@
 import se.llbit.chunky.renderer.scene.SceneManager;
 import se.llbit.chunky.ui.controller.ChunkyFxController;
 import se.llbit.chunky.ui.dialogs.SelectChunksInRadiusDialog;
-import se.llbit.chunky.ui.elements.TextFieldLabelWrapper;
 import se.llbit.chunky.world.*;
 import se.llbit.chunky.world.Dimension;
 import se.llbit.chunky.world.listeners.ChunkUpdateListener;
-import se.llbit.chunky.world.region.MCRegion;
+import se.llbit.chunky.world.region.Region;
 import se.llbit.log.Log;
 import se.llbit.math.*;
 
@@ -57,7 +50,6 @@
 import java.io.File;
 import java.io.IOException;
 import java.util.Collection;
-import java.util.Optional;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
@@ -227,8 +219,8 @@ public ChunkMap(WorldMapLoader loader, ChunkyFxController controller,
     if (view.chunkScale >= 16) {
       int minChunkX = region.x << 5;
       int minChunkZ = region.z << 5;
-      for (int chunkX = minChunkX; chunkX < minChunkX + MCRegion.CHUNKS_X; chunkX++) {
-        for (int chunkZ = minChunkZ; chunkZ < minChunkZ + MCRegion.CHUNKS_Z; chunkZ++) {
+      for (int chunkX = minChunkX; chunkX < minChunkX + Region.CHUNKS_X; chunkX++) {
+        for (int chunkZ = minChunkZ; chunkZ < minChunkZ + Region.CHUNKS_Z; chunkZ++) {
           mapBuffer.drawTile(mapLoader, new ChunkPosition(chunkX, chunkZ), chunkSelection);
         }
       }
@@ -596,18 +588,16 @@ private void drawPlayers(GraphicsContext gc) {
     World world = mapLoader.getWorld();
     double blockScale = mapView.scale / 16.;
     for (PlayerEntityData player : world.currentDimension().getPlayerPositions()) {
-      if (player.dimension.equals(world.currentDimension().getDimensionId())) {
-        int px = (int) QuickMath.floor(player.x * blockScale);
-        int py = (int) QuickMath.floor(player.y);
-        int pz = (int) QuickMath.floor(player.z * blockScale);
-        int ppx = px - (int) QuickMath.floor(mapView.x0 * mapView.scale);
-        int ppy = pz - (int) QuickMath.floor(mapView.z0 * mapView.scale);
-        int pw = (int) QuickMath.max(16, QuickMath.min(32, blockScale * 4));
-        ppx = Math.min(mapView.width - pw, Math.max(0, ppx - pw / 2));
-        ppy = Math.min(mapView.height - pw, Math.max(0, ppy - pw / 2));
-
-        gc.drawImage(Icon.player.fxImage(), ppx, ppy, pw, pw);
-      }
+      int px = (int) QuickMath.floor(player.x * blockScale);
+      int py = (int) QuickMath.floor(player.y);
+      int pz = (int) QuickMath.floor(player.z * blockScale);
+      int ppx = px - (int) QuickMath.floor(mapView.x0 * mapView.scale);
+      int ppy = pz - (int) QuickMath.floor(mapView.z0 * mapView.scale);
+      int pw = (int) QuickMath.max(16, QuickMath.min(32, blockScale * 4));
+      ppx = Math.min(mapView.width - pw, Math.max(0, ppx - pw / 2));
+      ppy = Math.min(mapView.height - pw, Math.max(0, ppy - pw / 2));
+
+      gc.drawImage(Icon.player.fxImage(), ppx, ppy, pw, pw);
     }
   }
 
diff --git a/chunky/src/java/se/llbit/chunky/ui/controller/ChunkyFxController.java b/chunky/src/java/se/llbit/chunky/ui/controller/ChunkyFxController.java
index c93aa97ffd..cb5cc071bb 100644
--- a/chunky/src/java/se/llbit/chunky/ui/controller/ChunkyFxController.java
+++ b/chunky/src/java/se/llbit/chunky/ui/controller/ChunkyFxController.java
@@ -23,12 +23,7 @@
 import java.nio.file.Path;
 import java.text.DecimalFormat;
 import java.time.Duration;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.IdentityHashMap;
-import java.util.Map;
-import java.util.Optional;
-import java.util.ResourceBundle;
+import java.util.*;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -286,7 +281,7 @@ public void exportMapView() {
     fileChooser.setTitle("Export PNG");
     fileChooser
         .getExtensionFilters().add(new FileChooser.ExtensionFilter("PNG image", "*.png"));
-    mapLoader.withWorld(world -> fileChooser.setInitialFileName(world.levelName() + ".png"));
+    mapLoader.withWorld(world -> fileChooser.setInitialFileName(world.getInfo().name() + ".png"));
     if (prevPngDir != null) {
       fileChooser.setInitialDirectory(prevPngDir.toFile());
     }
@@ -326,7 +321,7 @@ public void exportMapView() {
         World newWorld = scene.getWorld();
         World currentWorld = mapLoader.getWorld();
         boolean isSameWorld = currentWorld != EmptyWorld.INSTANCE &&
-          currentWorld.getWorldDirectory().equals(newWorld.getWorldDirectory());
+          currentWorld.getInfo().isSameWorld(newWorld.getInfo());
 
         if (isSameWorld) {
           getChunkSelection().setSelection(chunky.getSceneManager().getScene().getChunks());
@@ -340,7 +335,7 @@ public void exportMapView() {
               "This scene shows a different world than the one that is currently loaded. Do you want to load the world of this scene?");
             Dialogs.stayOnTop(loadWorldConfirm);
             if (loadWorldConfirm.showAndWait().orElse(ButtonType.CANCEL) == ButtonType.YES) {
-              mapLoader.loadWorld(newWorld.getWorldDirectory());
+              mapLoader.setWorld(newWorld);
               getChunkSelection().setSelection(chunky.getSceneManager().getScene().getChunks());
             }
           }
@@ -459,25 +454,20 @@ public File getSceneFile(String fileName) {
                 }
                 if (!reloaded) {
                   ignoreYUpdate.set(true);
-                  if (mapLoader.getWorld().getVersionId() >= World.VERSION_21W06A) {
-                    yMin.setRange(-64, 320);
-                    yMin.set(-64);
-                    yMax.setRange(-64, 320);
-                    yMax.set(320);
-                    mapView.setYMinMax(-64, 320);
-                  } else {
-                    yMin.setRange(0, 256);
-                    yMin.set(0);
-                    yMax.setRange(0, 256);
-                    yMax.set(256);
-                    mapView.setYMinMax(0, 256);
-                  }
+                  HeightRange heightRange = mapLoader.getWorld().currentDimension().heightRange();
+                  int min = heightRange.min();
+                  int max = heightRange.max();
+                  yMin.setRange(min, max);
+                  yMin.set(min);
+                  yMax.setRange(min, max);
+                  yMax.set(max);
+                  mapView.setYMinMax(min, max);
                   yMin.getStyleClass().removeAll("invalid");
                   yMax.getStyleClass().removeAll("invalid");
                   ignoreYUpdate.set(false);
                 }
                 map.redrawMap();
-                mapName.setText(world.levelName());
+                mapName.setText(world.getInfo().name());
                 showWorldMap();
               });
         });
@@ -656,14 +646,10 @@ public File getSceneFile(String fileName) {
     mapOverlay.setOnKeyPressed(map::onKeyPressed);
     mapOverlay.setOnKeyReleased(map::onKeyReleased);
 
-    mapLoader.loadWorld(PersistentSettings.getLastWorld());
-    if (mapLoader.getWorld().getVersionId() >= World.VERSION_21W06A) {
-      mapView.setYMin(-64);
-      mapView.setYMax(320);
-    } else {
-      mapView.setYMin(0);
-      mapView.setYMax(256);
-    }
+    mapLoader.loadWorldFromDirectory(PersistentSettings.getLastWorld(), PersistentSettings.getLastWorldFormat());
+    HeightRange heightRange = mapLoader.getWorld().currentDimension().heightRange();
+    mapView.setYMin(heightRange.min());
+    mapView.setYMax(heightRange.max());
 
     canvas = new RenderCanvasFx(this, chunky.getSceneManager().getScene(),
         chunky.getRenderController().getRenderManager());
diff --git a/chunky/src/java/se/llbit/chunky/ui/controller/WorldChooserController.java b/chunky/src/java/se/llbit/chunky/ui/controller/WorldChooserController.java
index 5705e9e625..6df657d0bb 100644
--- a/chunky/src/java/se/llbit/chunky/ui/controller/WorldChooserController.java
+++ b/chunky/src/java/se/llbit/chunky/ui/controller/WorldChooserController.java
@@ -31,11 +31,12 @@
 import se.llbit.chunky.map.WorldMapLoader;
 import se.llbit.chunky.resources.MinecraftFinder;
 import se.llbit.chunky.resources.ResourcePackLoader;
-import se.llbit.chunky.resources.TexturePackLoader;
 import se.llbit.chunky.ui.TableSortConfigSerializer;
+import se.llbit.chunky.world.EmptyWorld;
 import se.llbit.chunky.world.Dimension;
 import se.llbit.chunky.world.EmptyWorld;
 import se.llbit.chunky.world.World;
+import se.llbit.chunky.world.worldformat.WorldFormats;
 import se.llbit.fxutil.Dialogs;
 import se.llbit.json.JsonArray;
 import se.llbit.log.Log;
@@ -48,17 +49,17 @@
 public class WorldChooserController implements Initializable {
   @FXML private Label statusLabel;
 
-  @FXML private TableView<World> worldTbl;
+  @FXML private TableView<World.Info> worldTbl;
 
-  @FXML private TableColumn<World, String> worldNameCol;
+  @FXML private TableColumn<World.Info, String> worldNameCol;
 
-  @FXML private TableColumn<World, String> worldDirCol;
+  @FXML private TableColumn<World.Info, String> worldDirCol;
 
-  @FXML private TableColumn<World, String> gameModeCol;
+  @FXML private TableColumn<World.Info, String> gameModeCol;
 
-  @FXML private TableColumn<World, Number> seedCol;
+  @FXML private TableColumn<World.Info, Number> seedCol;
 
-  @FXML public TableColumn<World, Date> modifiedCol;
+  @FXML public TableColumn<World.Info, Date> modifiedCol;
 
   @FXML private Button changeWorldDirBtn;
 
@@ -69,15 +70,15 @@ public class WorldChooserController implements Initializable {
 
   @Override public void initialize(URL location, ResourceBundle resources) {
     worldNameCol
-        .setCellValueFactory(data -> new ReadOnlyStringWrapper(data.getValue().levelName()));
+        .setCellValueFactory(data -> new ReadOnlyStringWrapper(data.getValue().name()));
     worldDirCol.setCellValueFactory(
-        data -> new ReadOnlyStringWrapper(data.getValue().getWorldDirectory().getName()));
+        data -> new ReadOnlyStringWrapper(data.getValue().path().getFileName().toString()));
     gameModeCol.setCellValueFactory(data -> new ReadOnlyStringWrapper(data.getValue().gameMode()));
-    seedCol.setCellValueFactory(data -> new ReadOnlyLongWrapper(data.getValue().getSeed()));
+    seedCol.setCellValueFactory(data -> new ReadOnlyLongWrapper(data.getValue().seed()));
 
     DateFormat localeFormat = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.SHORT);
-    modifiedCol.setCellValueFactory(data -> new ReadOnlyObjectWrapper<>(data.getValue().getLastModified()));
-    modifiedCol.setCellFactory(col -> new TableCell<World, Date>() {
+    modifiedCol.setCellValueFactory(data -> new ReadOnlyObjectWrapper<>(new Date(data.getValue().lastModified())));
+    modifiedCol.setCellFactory(col -> new TableCell<>() {
       public void updateItem(Date item, boolean empty) {
         if (item == this.getItem()) return;
         super.updateItem(item, empty);
@@ -96,7 +97,7 @@ public void setStage(Stage stage) {
    */
   public void populate(WorldMapLoader mapLoader) {
     worldTbl.setRowFactory(tbl -> {
-      TableRow<World> row = new TableRow<>();
+      TableRow<World.Info> row = new TableRow<>();
       row.setOnMouseClicked(e -> {
         if (e.getClickCount() == 2 && !row.isEmpty()) {
           this.loadWorld(row.getItem(), mapLoader);
@@ -135,7 +136,12 @@ public void populate(WorldMapLoader mapLoader) {
       File directory = chooser.showDialog(stage);
       if (directory != null) {
         if (directory.isDirectory()) {
-          this.loadWorld(World.loadWorld(directory, mapLoader.getDimension(), World.LoggedWarnings.NORMAL), mapLoader);
+          Optional<World.Info> info = WorldFormats.getInfos(directory.toPath()).stream().findFirst(); // TODO: could ask which world format to load as
+          if (info.isPresent()) {
+            this.loadWorld(info.get(), mapLoader);
+          } else {
+            mapLoader.setWorld(EmptyWorld.INSTANCE);
+          }
           stage.close();
         } else {
           Log.warn("Non-directory selected.");
@@ -150,8 +156,9 @@ public void populate(WorldMapLoader mapLoader) {
     });
   }
 
-  private void loadWorld(World world, WorldMapLoader mapLoader) {
-    world.getResourcePack()
+  private void loadWorld(World.Info info, WorldMapLoader mapLoader) {
+    mapLoader.loadWorld(info)
+      .getResourcePack()
       .ifPresent(worldResourcePack -> {
         List<File> currentlyLoadedPacks = new ArrayList<>(ResourcePackLoader.getLoadedResourcePacks());
 
@@ -161,7 +168,7 @@ private void loadWorld(World world, WorldMapLoader mapLoader) {
           loadTexturesConfirm.getButtonTypes().addAll(ButtonType.YES, ButtonType.NO);
           loadTexturesConfirm.setTitle("Bundled resource pack");
           loadTexturesConfirm.setContentText(
-                  "The world \"" + world.levelName() + "\" contains a resource pack. Do you want to load it now?");
+            "The world \"" + info.name() + "\" contains a resource pack. Do you want to load it now?");
           Dialogs.stayOnTop(loadTexturesConfirm);
 
           if (loadTexturesConfirm.showAndWait().orElse(ButtonType.CANCEL) == ButtonType.YES) {
@@ -171,7 +178,6 @@ private void loadWorld(World world, WorldMapLoader mapLoader) {
           }
         }
       });
-    mapLoader.loadWorld(world.getWorldDirectory());
   }
 
   /**
@@ -188,20 +194,15 @@ private void fillWorldList(final File worldSavesDir) {
     statusLabel.setText("Loading worlds list...");
     disableControls(true);
 
-    Task<List<World>> loadWorldsTask = new Task<List<World>>() {
+    Task<List<World.Info>> loadWorldsTask = new Task<>() {
       @Override
-      protected List<World> call() {
-        List<World> worlds = new ArrayList<>();
+      protected List<World.Info> call() {
+        List<World.Info> worlds = new ArrayList<>();
         if (worldSavesDir != null) {
           File[] worldDirs = worldSavesDir.listFiles();
           if (worldDirs != null) {
             for (File dir : worldDirs) {
-              if (World.isWorldDir(dir)) {
-                World world = World.loadWorld(dir, Dimension.Identifier.OVERWORLD, World.LoggedWarnings.SILENT);
-                if (world != EmptyWorld.INSTANCE) {
-                  worlds.add(world);
-                }
-              }
+              worlds.addAll(WorldFormats.getInfos(dir.toPath()));
             }
           }
         }
@@ -210,7 +211,7 @@ protected List<World> call() {
     };
 
     loadWorldsTask.setOnSucceeded((WorkerStateEvent event) -> {
-      List<World> worlds = loadWorldsTask.getValue();
+      List<World.Info> worlds = loadWorldsTask.getValue();
 
       worldTbl.setItems(FXCollections.observableArrayList(worlds));
       if (!worlds.isEmpty()) {
diff --git a/chunky/src/java/se/llbit/chunky/ui/render/tabs/GeneralTab.java b/chunky/src/java/se/llbit/chunky/ui/render/tabs/GeneralTab.java
index 095e056f55..056c2381b5 100644
--- a/chunky/src/java/se/llbit/chunky/ui/render/tabs/GeneralTab.java
+++ b/chunky/src/java/se/llbit/chunky/ui/render/tabs/GeneralTab.java
@@ -17,6 +17,7 @@
  */
 package se.llbit.chunky.ui.render.tabs;
 
+import it.unimi.dsi.fastutil.ints.IntIntPair;
 import javafx.beans.binding.Bindings;
 import javafx.beans.value.ChangeListener;
 import javafx.fxml.FXML;
@@ -47,6 +48,7 @@
 import se.llbit.chunky.ui.elements.SizeInput;
 import se.llbit.chunky.ui.render.RenderControlsTab;
 import se.llbit.chunky.world.EmptyWorld;
+import se.llbit.chunky.world.HeightRange;
 import se.llbit.chunky.world.Icon;
 import se.llbit.chunky.world.World;
 import se.llbit.fxutil.Dialogs;
@@ -592,12 +594,14 @@ private void updateCanvasCrop() {
   }
 
   private void updateYClipSlidersRanges(World world) {
-    if (world != null && world.getVersionId() >= World.VERSION_21W06A) {
-      yMin.setRange(-64, 320);
-      yMax.setRange(-64, 320);
-    } else {
-      yMin.setRange(0, 256);
-      yMax.setRange(0, 256);
+    if (world != null) {
+      HeightRange heightRange = world.currentDimension().heightRange();
+      int min = heightRange.min();
+      int max = heightRange.max();
+      yMin.setRange(min, max);
+      yMin.set(min);
+      yMax.setRange(min, max);
+      yMax.set(max);
     }
   }
 }
diff --git a/chunky/src/java/se/llbit/chunky/world/Chunk.java b/chunky/src/java/se/llbit/chunky/world/Chunk.java
index 55599bbab8..7bed3349e7 100644
--- a/chunky/src/java/se/llbit/chunky/world/Chunk.java
+++ b/chunky/src/java/se/llbit/chunky/world/Chunk.java
@@ -17,35 +17,17 @@
 package se.llbit.chunky.world;
 
 import se.llbit.chunky.block.minecraft.Air;
-import it.unimi.dsi.fastutil.ints.IntIntImmutablePair;
 import se.llbit.chunky.block.Block;
 import se.llbit.chunky.block.minecraft.Lava;
 import se.llbit.chunky.block.minecraft.Water;
-import se.llbit.chunky.block.legacy.LegacyBlocks;
 import se.llbit.chunky.chunk.BlockPalette;
 import se.llbit.chunky.chunk.ChunkData;
 import se.llbit.chunky.chunk.ChunkLoadingException;
-import se.llbit.chunky.chunk.EmptyChunkData;
-import se.llbit.chunky.chunk.biome.BiomeDataFactory;
 import se.llbit.chunky.map.*;
-import se.llbit.chunky.world.biome.ArrayBiomePalette;
 import se.llbit.chunky.world.biome.BiomePalette;
-import se.llbit.chunky.world.region.MCRegion;
-import se.llbit.chunky.world.region.Region;
-import se.llbit.log.Log;
-import se.llbit.math.QuickMath;
-import se.llbit.nbt.*;
-import se.llbit.util.BitBuffer;
 import se.llbit.util.Mutable;
 import se.llbit.util.annotation.NotNull;
 
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
-
-import static se.llbit.util.NbtUtil.getTagFromNames;
-import static se.llbit.util.NbtUtil.tagFromMap;
-
 /**
  * This class represents a loaded or not-yet-loaded chunk in the world.
  * <p>
@@ -53,7 +35,7 @@
  *
  * @author Jesper Öqvist (jesper@llbit.se)
  */
-public class Chunk {
+public abstract class Chunk {
 
   public static final String DATAVERSION = ".DataVersion";
   public static final String LEVEL_HEIGHTMAP = ".Level.HeightMap";
@@ -87,7 +69,7 @@ public class Chunk {
   protected volatile AbstractLayer surface = IconLayer.UNKNOWN;
   protected volatile AbstractLayer biomes = IconLayer.UNKNOWN;
 
-  private final Dimension dimension;
+  protected final Dimension dimension;
 
   protected int dataTimestamp = 0;
   protected int surfaceTimestamp = 0;
@@ -112,27 +94,6 @@ public int biomeColor() {
     return biomes.getAvgColor();
   }
 
-  /**
-   * @param request fresh request set
-   * @return loaded data, or null if something went wrong
-   */
-  private Map<String, Tag> getChunkTags(Set<String> request) throws ChunkLoadingException {
-    MCRegion region = (MCRegion) dimension.getRegion(position.getRegionPosition());
-    Mutable<Integer> timestamp = new Mutable<>(dataTimestamp);
-    Map<String, Tag> chunkTags = region.getChunkTags(this.position, request, timestamp);
-    this.dataTimestamp = timestamp.get();
-    return chunkTags;
-  }
-
-  /**
-   * @param request fresh request set
-   * @return loaded data, or null if something went wrong
-   */
-  private Map<String, Tag> getEntityTags(Set<String> request) throws ChunkLoadingException {
-    MCRegion region = (MCRegion) dimension.getRegion(position.getRegionPosition());
-    return region.getEntityTags(this.position, request);
-  }
-
   /**
    * Reset the rendered layers in this chunk.
    */
@@ -148,208 +109,11 @@ public ChunkPosition getPosition() {
   }
 
   /**
-   * Parse the chunk from the region file and render the current
-   * layer, surface and cave maps.
+   * Parse the chunk from the region file and render the current layer, surface and cave maps.
+   *
    * @return whether the input chunkdata was modified
    */
-  public synchronized boolean loadChunk(@NotNull Mutable<ChunkData> chunkData, int yMin, int yMax) {
-    if (!shouldReloadChunk()) {
-      return false;
-    }
-
-    Set<String> request = new HashSet<>();
-    request.add(Chunk.DATAVERSION);
-    request.add(Chunk.LEVEL_SECTIONS);
-    request.add(Chunk.SECTIONS_POST_21W39A);
-    request.add(Chunk.LEVEL_BIOMES);
-    request.add(Chunk.BIOMES_POST_21W39A);
-    request.add(Chunk.LEVEL_HEIGHTMAP);
-
-    Map<String, Tag> dataMap;
-    try {
-      dataMap = getChunkTags(request);
-    } catch (ChunkLoadingException e) { // we don't want to crash the map view if a chunk fails to load, so we warn the user
-      Log.warn(String.format("Failed to load chunk %s", position), e);
-      return false;
-    }
-    // TODO: improve error handling here.
-    if (dataMap == null) {
-      return false;
-    }
-    Tag data = tagFromMap(dataMap);
-
-    surfaceTimestamp = dataTimestamp;
-    version = chunkVersion(data);
-    IntIntImmutablePair chunkBounds = inclusiveChunkBounds(data);
-    chunkData.set(this.dimension.createChunkData(chunkData.get(), chunkBounds.leftInt(), chunkBounds.rightInt()));
-    loadSurface(data, chunkData.get(), yMin, yMax);
-    biomesTimestamp = dataTimestamp;
-
-    dimension.chunkUpdated(position);
-    return true;
-  }
-
-  private void loadSurface(@NotNull Tag data, ChunkData chunkData, int yMin, int yMax) {
-    if (data == null) {
-      surface = IconLayer.CORRUPT;
-      return;
-    }
-
-    Heightmap heightmap = dimension.getHeightmap();
-    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
-    if (sections.isList()) {
-      if (version == ChunkVersion.PRE_FLATTENING || version == ChunkVersion.POST_FLATTENING) {
-        BiomePalette biomePalette = new ArrayBiomePalette();
-        BiomeDataFactory.loadBiomeData(chunkData, data, biomePalette, yMin, yMax);
-        biomes = new BiomeLayer(chunkData, biomePalette);
-
-        BlockPalette palette = new BlockPalette();
-        palette.unsynchronize(); //only this RegionParser will use this palette
-        loadBlockData(data, chunkData, palette, yMin, yMax);
-
-        int[] heightmapData = extractHeightmapData(data, chunkData);
-        updateHeightmap(heightmap, position, chunkData, heightmapData, palette, yMax);
-
-        surface = new SurfaceLayer(dimension.getDimensionId(), chunkData, palette, biomePalette, yMin, yMax, heightmapData);
-        queueTopography();
-      }
-    } else {
-      surface = IconLayer.CORRUPT;
-    }
-  }
-
-  private int[] extractHeightmapData(@NotNull Tag data, ChunkData chunkData) {
-    Tag heightmapTag = data.get(LEVEL_HEIGHTMAP);
-    if (heightmapTag.isIntArray(X_MAX * Z_MAX)) {
-      return heightmapTag.intArray();
-    } else {
-      int[] fallback = new int[X_MAX * Z_MAX];
-      for (int i = 0; i < fallback.length; ++i) {
-        fallback[i] = chunkData.maxY();
-      }
-      return fallback;
-    }
-  }
-
-  /** Detect Minecraft version that generated the chunk. */
-  private static ChunkVersion chunkVersion(@NotNull Tag data) {
-    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
-    if (sections.isList()) {
-      for (SpecificTag section : sections.asList()) {
-        if (!section.get("Palette").isList()) {
-          if (section.get("Blocks").isByteArray(SECTION_BYTES)) {
-            return ChunkVersion.PRE_FLATTENING;
-          }
-        }
-      }
-      return ChunkVersion.POST_FLATTENING;
-    }
-    return ChunkVersion.UNKNOWN;
-  }
-
-  private static void loadBlockData(@NotNull Tag data, @NotNull ChunkData chunkData,
-      BlockPalette blockPalette, int minY, int maxY) {
-
-    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
-    if (sections.isList()) {
-      for (SpecificTag section : sections.asList()) {
-        Tag yTag = section.get("Y");
-        int sectionY = yTag.byteValue();
-        int sectionMinBlockY = sectionY << 4;
-
-        if(sectionY < minY >> 4 || sectionY-1 > (maxY >> 4)+1)
-          continue; //skip parsing sections that are outside requested bounds
-
-        Tag blockPaletteTag = getTagFromNames(section, "Palette", "block_states\\palette");
-        if (blockPaletteTag.isList()) {
-          ListTag localBlockPalette = blockPaletteTag.asList();
-          // Bits per block:
-          int bpb = 4;
-          if (localBlockPalette.size() > 16) {
-            bpb = QuickMath.log2(QuickMath.nextPow2(localBlockPalette.size()));
-          }
-
-          int dataSize = (4096 * bpb) / 64;
-          Tag blockStates = getTagFromNames(section, "BlockStates", "block_states\\data");
-
-          if (blockStates.isLongArray(dataSize)) {
-            // since 20w17a, block states are aligned to 64-bit boundaries, so there are 64 % bpb
-            // unused bits per block state; if so, the array is longer than the expected data size
-            boolean isAligned = data.get(DATAVERSION).intValue() >= DATAVERSION_20W17A;
-            if (isAligned) {
-              // entries are 64-bit-padded, re-calculate the bits per block
-              // this is the dataSize calculation from above reverted, we know the actual data size
-              bpb = blockStates.longArray().length / 64;
-            }
-
-            int[] subpalette = new int[localBlockPalette.size()];
-            int paletteIndex = 0;
-            for (Tag item : localBlockPalette.asList()) {
-              subpalette[paletteIndex] = blockPalette.put(item);
-              paletteIndex += 1;
-            }
-            BitBuffer buffer = new BitBuffer(blockStates.longArray(), bpb, isAligned);
-            for (int y = 0; y < SECTION_Y_MAX; y++) {
-              int blockY = sectionMinBlockY + y;
-              for (int z = 0; z < Z_MAX; z++) {
-                for(int x = 0; x < X_MAX; x++) {
-                  int b0 = buffer.read();
-                  if (b0 < subpalette.length) {
-                    chunkData.setBlockAt(x, blockY, z, subpalette[b0]);
-                  }
-                }
-              }
-            }
-          } else {
-            // Single block palette
-            if (localBlockPalette.size() == 1) {
-              // Check it is not air block
-              int block = blockPalette.put(localBlockPalette.get(0));
-              if (block != blockPalette.airId) {
-                // Set the entire section
-                for (int y = 0; y < SECTION_Y_MAX; y++) {
-                  int blockY = sectionMinBlockY + y;
-                  for (int z = 0; z < Z_MAX; z++) {
-                    for(int x = 0; x < X_MAX; x++) {
-                      chunkData.setBlockAt(x, blockY, z, block);
-                    }
-                  }
-                }
-              }
-            }
-          }
-        } else {
-          int yOffset = sectionY & 0xFF;
-
-          Tag dataTag = section.get("Data");
-          byte[] blockDataBytes = new byte[(Chunk.X_MAX * Chunk.Y_MAX * Chunk.Z_MAX) / 2];
-          if (dataTag.isByteArray(SECTION_HALF_NIBBLES)) {
-            System.arraycopy(dataTag.byteArray(), 0, blockDataBytes, SECTION_HALF_NIBBLES * yOffset,
-                SECTION_HALF_NIBBLES);
-          }
-
-          Tag blocksTag = section.get("Blocks");
-          if (blocksTag.isByteArray(SECTION_BYTES)) {
-            byte[] blocksBytes = new byte[Chunk.X_MAX * Chunk.Y_MAX * Chunk.Z_MAX];
-            System.arraycopy(blocksTag.byteArray(), 0, blocksBytes, SECTION_BYTES * yOffset,
-                SECTION_BYTES);
-
-            int offset = SECTION_BYTES * yOffset;
-            for (int y = 0; y < SECTION_Y_MAX; y++) {
-              int blockY = sectionMinBlockY + y;
-              for (int z = 0; z < Z_MAX; z++) {
-                for (int x = 0; x < X_MAX; x++) {
-                  chunkData.setBlockAt(x, blockY, z, blockPalette.put(
-                      LegacyBlocks.getTag(offset, blocksBytes, blockDataBytes)));
-                  offset += 1;
-                }
-              }
-            }
-          }
-        }
-      }
-    }
-  }
+  public abstract boolean loadChunk(@NotNull Mutable<ChunkData> chunkData, int yMin, int yMax);
 
   /**
    * Load heightmap information from a chunk heightmap array
@@ -370,17 +134,6 @@ protected static void updateHeightmap(Heightmap heightmap, ChunkPosition pos, Ch
     }
   }
 
-  protected boolean shouldReloadChunk() {
-    int timestamp = Integer.MAX_VALUE;
-    timestamp = Math.min(timestamp, surfaceTimestamp);
-    timestamp = Math.min(timestamp, biomesTimestamp);
-    if (timestamp == 0) {
-      return true;
-    }
-    Region region = dimension.getRegion(position.getRegionPosition());
-    return region.chunkChangedSince(position, timestamp);
-  }
-
   protected void queueTopography() {
     for (int x = -1; x <= 1; ++x) {
       for (int z = -1; z <= 1; ++z) {
@@ -445,97 +198,7 @@ public synchronized void renderTopography() {
    * @param maxY The requested maximum Y to be loaded into the chunkData object. The chunk implementation does NOT have to respect it
    * @throws ChunkLoadingException If there is an issue loading the chunk, and it should be aborted
    */
-  public synchronized void getChunkData(@NotNull Mutable<ChunkData> reuseChunkData, BlockPalette palette, BiomePalette biomePalette, int minY, int maxY) throws ChunkLoadingException {
-    Set<String> request = new HashSet<>();
-    request.add(DATAVERSION);
-    request.add(LEVEL_SECTIONS);
-    request.add(SECTIONS_POST_21W39A);
-    request.add(LEVEL_BIOMES);
-    request.add(BIOMES_POST_21W39A);
-    request.add(LEVEL_ENTITIES);
-    request.add(LEVEL_TILEENTITIES);
-    request.add(BLOCK_ENTITIES_POST_21W43A);
-    Map<String, Tag> dataMap = getChunkTags(request);
-    // TODO: improve error handling here.
-    if (dataMap == null) {
-      throw new ChunkLoadingException(String.format("Got null data for chunk %s", this.position));
-    }
-    Tag data = tagFromMap(dataMap);
-
-    int dataVersion = data.get(DATAVERSION).intValue();
-
-    IntIntImmutablePair chunkBounds = inclusiveChunkBounds(data);
-
-    if(reuseChunkData.get() == null || reuseChunkData.get() instanceof EmptyChunkData) {
-      reuseChunkData.set(dimension.createChunkData(reuseChunkData.get(), chunkBounds.leftInt(), chunkBounds.rightInt()));
-    } else {
-      reuseChunkData.get().clear();
-    }
-    ChunkData chunkData = reuseChunkData.get(); //unwrap mutable, for ease of use
-
-    version = chunkVersion(data);
-    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
-    Tag entitiesTag = data.get(LEVEL_ENTITIES);
-    Tag tileEntitiesTag = getTagFromNames(data, LEVEL_TILEENTITIES, BLOCK_ENTITIES_POST_21W43A);
-
-    BiomeDataFactory.loadBiomeData(chunkData, data, biomePalette, minY, maxY);
-    if (sections.isList()) {
-      loadBlockData(data, chunkData, palette, minY, maxY);
-
-      if (entitiesTag.isList()) {
-        for (SpecificTag tag : (ListTag) entitiesTag) {
-          if (tag.isCompoundTag())
-            chunkData.addEntity((CompoundTag) tag);
-        }
-      }
-
-      if (tileEntitiesTag.isList()) {
-        for (SpecificTag tag : (ListTag) tileEntitiesTag) {
-          if (tag.isCompoundTag())
-            chunkData.addTileEntity((CompoundTag) tag);
-        }
-      }
-    }
-
-    // post 20w45A entities
-    if (dataVersion >= DATAVERSION_20W45A) {
-      Set<String> entitiesRequest = new HashSet<>();
-      entitiesRequest.add(ENTITIES_POST_20W45A);
-
-      Map<String, Tag> entitiesMap = getEntityTags(entitiesRequest);
-      if (entitiesMap != null) {
-        entitiesTag = entitiesMap.get(".Entities");
-        if (entitiesTag.isList()) {
-          for (SpecificTag tag : (ListTag) entitiesTag) {
-            if (tag.isCompoundTag())
-              chunkData.addEntity((CompoundTag) tag);
-          }
-        }
-      }
-    }
-  }
-
-  /**
-   * @return The min and max blockY for a given section array
-   */
-  private IntIntImmutablePair inclusiveChunkBounds(Tag chunkData) {
-    Tag sections = getTagFromNames(chunkData, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
-    int minSectionY = Integer.MAX_VALUE;
-    int maxSectionY = Integer.MIN_VALUE;
-    if (sections.isList()) {
-      for (SpecificTag section : sections.asList()) {
-        byte sectionY = (byte) section.get("Y").byteValue();
-        if (sectionY < minSectionY) {
-          minSectionY = sectionY;
-        }
-        if (sectionY > maxSectionY) {
-          maxSectionY = sectionY;
-        }
-      }
-    }
-
-    return new IntIntImmutablePair(minSectionY << 4, (maxSectionY << 4) + 15);
-  }
+  public abstract void getChunkData(@NotNull Mutable<ChunkData> reuseChunkData, BlockPalette palette, BiomePalette biomePalette, int minY, int maxY) throws ChunkLoadingException;
 
   /**
    * @return Integer index into a chunk YXZ array
diff --git a/chunky/src/java/se/llbit/chunky/world/ChunkSelectionTracker.java b/chunky/src/java/se/llbit/chunky/world/ChunkSelectionTracker.java
index 2c1751c914..989931d74b 100644
--- a/chunky/src/java/se/llbit/chunky/world/ChunkSelectionTracker.java
+++ b/chunky/src/java/se/llbit/chunky/world/ChunkSelectionTracker.java
@@ -20,7 +20,7 @@
 import it.unimi.dsi.fastutil.objects.Object2ReferenceOpenHashMap;
 import se.llbit.chunky.world.listeners.ChunkDeletionListener;
 import se.llbit.chunky.world.listeners.ChunkUpdateListener;
-import se.llbit.chunky.world.region.MCRegion;
+import se.llbit.chunky.world.region.Region;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
@@ -42,7 +42,7 @@ public class ChunkSelectionTracker implements ChunkDeletionListener {
    */
   private boolean setChunk(ChunkPosition pos, boolean selected) {
     long regionPosLong = ChunkPosition.positionToLong(pos.x >> 5, pos.z >> 5);
-    BitSet selectedChunksForRegion = selectedChunksByRegion.computeIfAbsent(regionPosLong, p -> new BitSet(MCRegion.CHUNKS_X * MCRegion.CHUNKS_Z));
+    BitSet selectedChunksForRegion = selectedChunksByRegion.computeIfAbsent(regionPosLong, p -> new BitSet(Region.CHUNKS_X * Region.CHUNKS_Z));
     int bitIndex = (pos.x & 31) + ((pos.z & 31) << 5);
     boolean previousValue = selectedChunksForRegion.get(bitIndex);
     if(previousValue != selected) {
@@ -75,7 +75,7 @@ private boolean setChunk(Dimension dimension, ChunkPosition pos, boolean selecte
    * @return Whether the selection changed
    */
   private boolean setChunksWithinRegion(Dimension dimension, RegionPosition regionPos, int minX, int maxX, int minZ, int maxZ, boolean selected) {
-    BitSet selectedChunksForRegion = selectedChunksByRegion.computeIfAbsent(regionPos.getLong(), p -> new BitSet(MCRegion.CHUNKS_X * MCRegion.CHUNKS_Z));
+    BitSet selectedChunksForRegion = selectedChunksByRegion.computeIfAbsent(regionPos.getLong(), p -> new BitSet(Region.CHUNKS_X * Region.CHUNKS_Z));
 
     Collection<ChunkPosition> changedChunks = new ArrayList<>();
     boolean selectionChanged = false;
@@ -249,15 +249,15 @@ public synchronized boolean setChunks(Dimension dimension, int minChunkX, int mi
     boolean selectionChanged = false;
 
     // If selection area must contain complete regions
-    if(maxChunkX - minChunkX >= MCRegion.CHUNKS_X*2 && maxChunkZ - minChunkZ >= MCRegion.CHUNKS_Z*2) {
+    if(maxChunkX - minChunkX >= Region.CHUNKS_X*2 && maxChunkZ - minChunkZ >= Region.CHUNKS_Z*2) {
       // All full regions are set first, then any chunks on the borders are set, top and bottom include corners, left and right don't
 
       // left, right, top, bottom are unrelated to the actual map view, and are just treating XZ as if they were XY on traditional cartesian coordinate axes
-      int leftBorder = MCRegion.CHUNKS_X - (minChunkX & (MCRegion.CHUNKS_X-1)); // want the border from minimum region corner to minimum chunk corner, so 32 - borderSize
-      int rightBorder = maxChunkX & (MCRegion.CHUNKS_X-1);
+      int leftBorder = Region.CHUNKS_X - (minChunkX & (Region.CHUNKS_X-1)); // want the border from minimum region corner to minimum chunk corner, so 32 - borderSize
+      int rightBorder = maxChunkX & (Region.CHUNKS_X-1);
 
-      int bottomBorder = MCRegion.CHUNKS_Z - (minChunkZ & (MCRegion.CHUNKS_Z-1));
-      int topBorder = maxChunkZ & (MCRegion.CHUNKS_Z-1);
+      int bottomBorder = Region.CHUNKS_Z - (minChunkZ & (Region.CHUNKS_Z-1));
+      int topBorder = maxChunkZ & (Region.CHUNKS_Z-1);
 
       int minInnerRegionX = (minChunkX + leftBorder) >> 5;
       int maxInnerRegionX = (maxChunkX - rightBorder) >> 5;
@@ -397,9 +397,9 @@ public synchronized Map<RegionPosition, List<ChunkPosition>> getSelectionByRegio
     selectedChunksByRegion.forEach((regionPosition, selectedChunksBitSet) -> {
       RegionPosition regionPos = new RegionPosition(regionPosition);
       List<ChunkPosition> positions = new ArrayList<>();
-      for (int localX = 0; localX < MCRegion.CHUNKS_X; localX++) {
-        for (int localZ = 0; localZ < MCRegion.CHUNKS_Z; localZ++) {
-          int idx = localX + (localZ * MCRegion.CHUNKS_X);
+      for (int localX = 0; localX < Region.CHUNKS_X; localX++) {
+        for (int localZ = 0; localZ < Region.CHUNKS_Z; localZ++) {
+          int idx = localX + (localZ * Region.CHUNKS_X);
           if(selectedChunksBitSet.get(idx)) {
             positions.add(regionPos.asChunkPosition(localX, localZ));
           }
diff --git a/chunky/src/java/se/llbit/chunky/world/CubicDimension.java b/chunky/src/java/se/llbit/chunky/world/CubicDimension.java
index 778f3a69d1..f2e17d6443 100644
--- a/chunky/src/java/se/llbit/chunky/world/CubicDimension.java
+++ b/chunky/src/java/se/llbit/chunky/world/CubicDimension.java
@@ -3,9 +3,13 @@
 import se.llbit.chunky.chunk.ChunkData;
 import se.llbit.chunky.chunk.GenericChunkData;
 import se.llbit.chunky.chunk.biome.BiomeData2d;
+import se.llbit.chunky.world.java.JavaDimension;
+import se.llbit.chunky.world.java.JavaWorld;
 import se.llbit.chunky.world.region.EmptyRegion;
 import se.llbit.chunky.world.region.ImposterCubicRegion;
 import se.llbit.chunky.world.region.Region;
+import se.llbit.math.Vector3i;
+import se.llbit.util.annotation.Nullable;
 
 import java.io.File;
 import java.io.IOException;
@@ -17,13 +21,13 @@
 import static se.llbit.chunky.world.region.ImposterCubicRegion.blockToCube;
 import static se.llbit.chunky.world.region.ImposterCubicRegion.cubeToCubicRegion;
 
-public class CubicDimension extends Dimension {
+public class CubicDimension extends JavaDimension {
 
   /**
    * @param dimensionDirectory Minecraft world directory.
    */
-  protected CubicDimension(World world, Dimension.Identifier dimensionId, File dimensionDirectory, Set<PlayerEntityData> playerEntities) {
-    super(world, dimensionId, dimensionDirectory, playerEntities);
+  public CubicDimension(JavaWorld world, Dimension.Identifier dimensionId, Path dimensionDirectory, Set<PlayerEntityData> playerEntities, @Nullable Vector3i spawnPos) {
+    super(world, dimensionId, dimensionDirectory, playerEntities, spawnPos);
   }
 
   /**
@@ -31,7 +35,7 @@ protected CubicDimension(World world, Dimension.Identifier dimensionId, File dim
    */
   @Override
   public synchronized File getRegionDirectory() {
-    return new File(dimensionDirectory, "region3d");
+    return dimensionDirectory.resolve("region3d").toFile();
   }
 
   @Override
@@ -49,11 +53,11 @@ public Region createRegion(RegionPosition pos) {
     return new ImposterCubicRegion(pos, this);
   }
 
-  public synchronized Region getRegionWithinRange(RegionPosition pos, int minY, int maxY) {
+  public synchronized Region getRegionWithinRange(RegionPosition pos, HeightRange heightRange) {
     return regionMap.computeIfAbsent(pos.getLong(), p -> {
       // check if the region is present in the world directory
       Region region = EmptyRegion.instance;
-      if (regionExistsWithinRange(pos, minY, maxY)) {
+      if (this.hasRegionWithinRange(pos, heightRange)) {
         region = createRegion(pos);
       }
       return region;
@@ -62,10 +66,9 @@ public synchronized Region getRegionWithinRange(RegionPosition pos, int minY, in
 
   /** no choice but to iterate over every file in the directory */
   @Override
-  public boolean regionExists(RegionPosition pos) {
+  public boolean hasRegion(RegionPosition pos) {
     File regionDirectory = getRegionDirectory();
-    try {
-      Stream<Path> list = Files.list(regionDirectory.toPath());
+    try (Stream<Path> list = Files.list(regionDirectory.toPath())) {
       return list.anyMatch(path -> {
         String[] split = path.getFileName().toString().split("[.]");
         if(split.length == 4) {
@@ -83,13 +86,13 @@ public boolean regionExists(RegionPosition pos) {
   }
 
   @Override
-  public boolean regionExistsWithinRange(RegionPosition pos, int minY, int maxY) {
+  public boolean hasRegionWithinRange(RegionPosition pos, HeightRange heightRange) {
     int cubicRegionX = pos.x << 1;
     int cubicRegionZ = pos.z << 1;
 
     File regionDirectory = getRegionDirectory();
-    int minRegionY = cubeToCubicRegion(blockToCube(minY));
-    int maxRegionY = cubeToCubicRegion(blockToCube(maxY - 1));
+    int minRegionY = cubeToCubicRegion(blockToCube(heightRange().min()));
+    int maxRegionY = cubeToCubicRegion(blockToCube(heightRange.max() - 1));
     for (int y = minRegionY; y <= maxRegionY; y++) {
       for (int localX = 0; localX < ImposterCubicRegion.DIAMETER_IN_CUBIC_REGIONS; localX++) {
         for (int localZ = 0; localZ < ImposterCubicRegion.DIAMETER_IN_CUBIC_REGIONS; localZ++) {
diff --git a/chunky/src/java/se/llbit/chunky/world/Dimension.java b/chunky/src/java/se/llbit/chunky/world/Dimension.java
index 34c0b2b8ee..7a42e35d8b 100644
--- a/chunky/src/java/se/llbit/chunky/world/Dimension.java
+++ b/chunky/src/java/se/llbit/chunky/world/Dimension.java
@@ -1,7 +1,5 @@
 package se.llbit.chunky.world;
 
-import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
-import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import se.llbit.chunky.PersistentSettings;
 import se.llbit.chunky.chunk.ChunkData;
 import se.llbit.chunky.chunk.GenericChunkData;
@@ -17,13 +15,13 @@
 import se.llbit.math.Vector3i;
 import se.llbit.util.annotation.Nullable;
 
-import java.io.File;
+import java.nio.file.Path;
 import java.util.*;
 
 /**
  *
  */
-public class Dimension {
+public abstract class Dimension {
   public record Identifier(String namespace, String name) {
     public static Identifier OVERWORLD = new Identifier("minecraft", "overworld");
     public static Identifier THE_NETHER = new Identifier("minecraft", "the_nether");
@@ -63,77 +61,52 @@ public String toString() {
     }
   }
 
-  private final World world;
+  protected final Path dimensionDirectory;
 
-  protected final Long2ObjectMap<Region> regionMap = new Long2ObjectOpenHashMap<>();
+  protected final Heightmap heightmap = new Heightmap();
 
-  protected final File dimensionDirectory;
-  private Set<PlayerEntityData> playerEntities;
+  protected final Identifier dimensionId;
 
-  private final Heightmap heightmap = new Heightmap();
+  @Nullable protected final Vector3i spawnPos;
+  protected final Set<PlayerEntityData> playerEntities;
 
-  private final Identifier dimensionId;
-
-  private final Collection<ChunkDeletionListener> chunkDeletionListeners = new LinkedList<>();
-  private final Collection<ChunkTopographyListener> chunkTopographyListeners = new LinkedList<>();
-  private final Collection<ChunkUpdateListener> chunkUpdateListeners = new LinkedList<>();
-
-  private Vector3i spawnPos = null;
+  protected final Collection<ChunkDeletionListener> chunkDeletionListeners = new LinkedList<>();
+  protected final Collection<ChunkTopographyListener> chunkTopographyListeners = new LinkedList<>();
+  protected final Collection<ChunkUpdateListener> chunkUpdateListeners = new LinkedList<>();
 
   /**
    * @param dimensionDirectory Minecraft world directory.
    */
-  protected Dimension(World world, Identifier dimensionId, File dimensionDirectory, Set<PlayerEntityData> playerEntities) {
-    this.world = world;
+  protected Dimension(Identifier dimensionId, Path dimensionDirectory, Set<PlayerEntityData> playerEntities, @Nullable Vector3i spawnPos) {
     this.dimensionId = dimensionId;
-    this.dimensionDirectory = dimensionDirectory;
     this.playerEntities = playerEntities;
-  }
-
-  public Identifier getDimensionId() {
-    return dimensionId;
+    this.dimensionDirectory = dimensionDirectory;
+    this.spawnPos = spawnPos;
   }
 
   /**
-   * Reload player data.
-   *
-   * @return {@code true} if player data was reloaded.
+   * @return A user presentable name of the dimension
    */
-  public synchronized boolean reloadPlayerData() {
-    return this.world.reloadPlayerData();
-  }
+  public abstract String getName();
 
-  /**
-   * Add a chunk deletion listener.
-   */
-  public void addChunkDeletionListener(ChunkDeletionListener listener) {
-    synchronized (chunkDeletionListeners) {
-      chunkDeletionListeners.add(listener);
-    }
+  public Identifier getDimensionId() {
+    return dimensionId;
   }
 
   /**
-   * Add a region discovery listener.
+   * Get the data directory for the given dimension.
+   * <p>This may be the same as the world directory for some dimensions</p>
+   *
+   * @return The path to the dimension
    */
-  public void addChunkUpdateListener(ChunkUpdateListener listener) {
-    synchronized (chunkUpdateListeners) {
-      chunkUpdateListeners.add(listener);
-    }
-  }
-
-  private void fireChunkDeleted(ChunkPosition chunk) {
-    synchronized (chunkDeletionListeners) {
-      for (ChunkDeletionListener listener : chunkDeletionListeners)
-        listener.chunkDeleted(chunk);
-    }
+  protected synchronized Path getDimensionPath() {
+    return dimensionDirectory;
   }
 
   /**
    * @return The chunk at the given position
    */
-  public synchronized Chunk getChunk(ChunkPosition pos) {
-    return getRegion(pos.getRegionPosition()).getChunk(pos);
-  }
+  public abstract Chunk getChunk(ChunkPosition pos);
 
   /**
    * Returns a ChunkData instance that is compatible with the given chunk version.
@@ -153,147 +126,134 @@ public ChunkData createChunkData(@Nullable ChunkData chunkData, int minY, int ma
     return new GenericChunkData();
   }
 
-  public Region createRegion(RegionPosition pos) {
-    return new MCRegion(pos, this);
-  }
+  public abstract Region createRegion(RegionPosition pos);
 
-  public RegionChangeWatcher createRegionChangeWatcher(WorldMapLoader worldMapLoader, MapView mapView) {
-    return new MCRegionChangeWatcher(worldMapLoader, mapView);
-  }
+  public abstract RegionChangeWatcher createRegionChangeWatcher(WorldMapLoader worldMapLoader, MapView mapView);
 
   /**
    * @param pos Region position
    * @return The region at the given position
    */
-  public synchronized Region getRegion(RegionPosition pos) {
-    return regionMap.computeIfAbsent(pos.getLong(), p -> {
-      // check if the region is present in the world directory
-      Region region = EmptyRegion.instance;
-      if (regionExists(pos)) {
-        region = createRegion(pos);
-      }
-      return region;
-    });
-  }
-
-  public Region getRegionWithinRange(RegionPosition pos, int yMin, int yMax) {
-    return getRegion(pos);
-  }
+  public abstract Region getRegion(RegionPosition pos);
 
-  /**
-   * Set the region for the given position.
-   */
-  public synchronized void setRegion(RegionPosition pos, Region region) {
-    regionMap.put(pos.getLong(), region);
-  }
+  public abstract Region getRegionWithinRange(RegionPosition pos, HeightRange heightRange);
 
   /**
    * @param pos region position
    * @return {@code true} if a region file exists for the given position
    */
-  public boolean regionExists(RegionPosition pos) {
-    File regionFile = new File(getRegionDirectory(), pos.getMcaName());
-    return regionFile.exists();
-  }
+  public abstract boolean hasRegion(RegionPosition pos);
 
   /**
    * @param pos  Position of the region to load
-   * @param minY Minimum block Y (inclusive)
-   * @param maxY Maximum block Y (exclusive)
+   * @param heightRange The height range of the request
    * @return Whether the region exists
    */
-  public boolean regionExistsWithinRange(RegionPosition pos, int minY, int maxY) {
-    return this.regionExists(pos);
-  }
+  public abstract boolean hasRegionWithinRange(RegionPosition pos, HeightRange heightRange);
 
   /**
-   * Get the data directory for the given dimension.
+   * WARNING: In some dimensions this could be from {@link Integer#MIN_VALUE} to {@link Integer#MAX_VALUE}
+   * <p>
+   * Lower bound is inclusive, upper is exclusive
    *
-   * @return File object pointing to the data directory
+   * @return The height range of the dimension.
    */
-  protected synchronized File getDimensionDirectory() {
-    return dimensionDirectory;
-  }
+  public abstract HeightRange heightRange();
 
   /**
-   * @return File object pointing to the region file directory
+   * @return The chunk heightmap
    */
-  public synchronized File getRegionDirectory() {
-    return new File(getDimensionDirectory(), "region");
+  public Heightmap getHeightmap() {
+    return heightmap;
   }
 
+  public Optional<Vector3i> getSpawnPosition() {
+    return Optional.ofNullable(this.spawnPos);
+  }
+
+  /**
+   * Reload player data.
+   *
+   * @return {@code true} if player data was reloaded.
+   */
+  public abstract boolean reloadPlayerData();
+
   /**
    * Get the current player position as an optional vector.
    *
    * <p>The result is empty if this is not a single player world.
    */
-  public synchronized Optional<Vector3> getPlayerPos() {
-    if (!playerEntities.isEmpty()) {
-      return world.getSingleplayerPlayerUuid()
-        .flatMap(uuid -> playerEntities.stream()
-          .filter(player -> player.uuid.equals(uuid))
-          .map(pos -> new Vector3(pos.x, pos.y, pos.z))
-          .findFirst());
-    } else {
-      return Optional.empty();
-    }
-  }
+  public abstract Optional<Vector3> getPlayerPos();
 
   /**
-   * @return The chunk heightmap
+   * Load entities from world the file.
+   * This is usually the single player entity in a local save.
    */
-  public Heightmap getHeightmap() {
-    return heightmap;
+  public synchronized Collection<PlayerEntity> getPlayerEntities() {
+    Collection<PlayerEntity> list = new LinkedList<>();
+    if (PersistentSettings.getLoadPlayers()) {
+      for (PlayerEntityData data : playerEntities) {
+        list.add(new PlayerEntity(data));
+      }
+    }
+    return list;
+  }
+
+  public synchronized Collection<PlayerEntityData> getPlayerPositions() {
+    return Collections.unmodifiableSet(playerEntities);
   }
 
   /**
-   * Called when a new region has been discovered by the region parser.
+   * Add a chunk deletion listener.
    */
-  public void regionDiscovered(RegionPosition pos) {
-    synchronized (this) {
-      regionMap.computeIfAbsent(pos.getLong(), p -> createRegion(pos));
+  public void addChunkDeletionListener(ChunkDeletionListener listener) {
+    synchronized (chunkDeletionListeners) {
+      chunkDeletionListeners.add(listener);
     }
   }
 
   /**
-   * Notify region update listeners.
+   * Called when chunks have been deleted from this world.
+   * Triggers the chunk deletion listeners.
+   *
+   * @param pos Position of deleted chunk
    */
-  private void fireChunkUpdated(ChunkPosition chunk) {
-    synchronized (chunkUpdateListeners) {
-      for (ChunkUpdateListener listener : chunkUpdateListeners) {
-        listener.chunkUpdated(chunk);
-      }
+  public void chunkDeleted(ChunkPosition pos) {
+    synchronized (chunkDeletionListeners) {
+      for (ChunkDeletionListener listener : chunkDeletionListeners)
+        listener.chunkDeleted(pos);
     }
   }
 
   /**
-   * Notify region update listeners.
+   * Add a region discovery listener.
    */
-  private void fireRegionUpdated(RegionPosition region) {
+  public void addChunkUpdateListener(ChunkUpdateListener listener) {
     synchronized (chunkUpdateListeners) {
-      for (ChunkUpdateListener listener : chunkUpdateListeners) {
-        listener.regionUpdated(region);
-      }
+      chunkUpdateListeners.add(listener);
     }
   }
 
-  @Override
-  public String toString() {
-    return dimensionDirectory.getName();
-  }
-
   /**
    * Called when a chunk has been updated.
    */
   public void chunkUpdated(ChunkPosition chunk) {
-    fireChunkUpdated(chunk);
+    synchronized (chunkUpdateListeners) {
+      for (ChunkUpdateListener listener : chunkUpdateListeners) {
+        listener.chunkUpdated(chunk);
+      }
+    }
   }
 
   /**
    * Called when a chunk has been updated.
    */
   public void regionUpdated(RegionPosition region) {
-    fireRegionUpdated(region);
+    synchronized (chunkUpdateListeners) {
+      for (ChunkUpdateListener listener : chunkUpdateListeners) {
+        listener.regionUpdated(region);
+      }
+    }
   }
 
   /**
@@ -324,48 +284,4 @@ public void chunkTopographyUpdated(Chunk chunk) {
       listener.chunksTopographyUpdated(chunk);
     }
   }
-
-  public Optional<Vector3i> getSpawnPosition() {
-    return Optional.ofNullable(this.spawnPos);
-  }
-
-  public void setSpawnPos(@Nullable Vector3i spawnPos) {
-    this.spawnPos = spawnPos;
-  }
-
-  /**
-   * Called when chunks have been deleted from this world.
-   * Triggers the chunk deletion listeners.
-   *
-   * @param pos Position of deleted chunk
-   */
-  public void chunkDeleted(ChunkPosition pos) {
-    fireChunkDeleted(pos);
-  }
-
-  public Date getLastModified() {
-    return new Date(this.dimensionDirectory.lastModified());
-  }
-
-  /**
-   * Load entities from world the file.
-   * This is usually the single player entity in a local save.
-   */
-  public synchronized Collection<PlayerEntity> getPlayerEntities() {
-    Collection<PlayerEntity> list = new LinkedList<>();
-    if (PersistentSettings.getLoadPlayers()) {
-      for (PlayerEntityData data : playerEntities) {
-        list.add(new PlayerEntity(data));
-      }
-    }
-    return list;
-  }
-
-  public synchronized Collection<PlayerEntityData> getPlayerPositions() {
-    return Collections.unmodifiableSet(playerEntities);
-  }
-
-  public synchronized void setPlayerEntities(Set<PlayerEntityData> playerEntities) {
-    this.playerEntities = playerEntities;
-  }
 }
diff --git a/chunky/src/java/se/llbit/chunky/world/EmptyChunk.java b/chunky/src/java/se/llbit/chunky/world/EmptyChunk.java
index dd1ed4a263..7065e224cb 100644
--- a/chunky/src/java/se/llbit/chunky/world/EmptyChunk.java
+++ b/chunky/src/java/se/llbit/chunky/world/EmptyChunk.java
@@ -24,6 +24,7 @@
 import se.llbit.chunky.ui.ChunkMap;
 import se.llbit.chunky.world.biome.BiomePalette;
 import se.llbit.util.Mutable;
+import se.llbit.util.annotation.NotNull;
 
 /**
  * Empty or non-existent chunk in a region that <b>does</b> exist.
@@ -86,7 +87,7 @@ private void renderEmpty(MapTile tile) {
     // Do nothing.
   }
 
-  @Override public synchronized boolean loadChunk(Mutable<ChunkData> chunkData, int yMin, int yMax) {
+  @Override public synchronized boolean loadChunk(@NotNull Mutable<ChunkData> chunkData, int yMin, int yMax) {
     return false;
   }
 
diff --git a/chunky/src/java/se/llbit/chunky/world/EmptyDimension.java b/chunky/src/java/se/llbit/chunky/world/EmptyDimension.java
index cf112ff995..e627aebe74 100644
--- a/chunky/src/java/se/llbit/chunky/world/EmptyDimension.java
+++ b/chunky/src/java/se/llbit/chunky/world/EmptyDimension.java
@@ -1,14 +1,76 @@
 package se.llbit.chunky.world;
 
+import it.unimi.dsi.fastutil.ints.IntIntImmutablePair;
+import it.unimi.dsi.fastutil.ints.IntIntPair;
+import se.llbit.chunky.map.MapView;
+import se.llbit.chunky.map.WorldMapLoader;
+import se.llbit.chunky.world.region.EmptyRegion;
+import se.llbit.chunky.world.region.Region;
+import se.llbit.chunky.world.region.RegionChangeWatcher;
+import se.llbit.math.Vector3;
+
 import java.util.Collections;
+import java.util.Optional;
 
 public class EmptyDimension extends Dimension {
   EmptyDimension() {
-    super(EmptyWorld.INSTANCE, Dimension.Identifier.OVERWORLD, null, Collections.emptySet());
+    super(Dimension.Identifier.OVERWORLD, null, Collections.emptySet(), null);
+  }
+
+  @Override
+  public Chunk getChunk(ChunkPosition pos) {
+    return EmptyChunk.INSTANCE;
+  }
+
+  @Override
+  public Region createRegion(RegionPosition pos) {
+    return EmptyRegion.instance;
+  }
+
+  @Override
+  public RegionChangeWatcher createRegionChangeWatcher(WorldMapLoader worldMapLoader, MapView mapView) {
+    return new RegionChangeWatcher(worldMapLoader, mapView, "Empty Region Change Watcher") {
+      @Override
+      public void run() {}
+    };
+  }
+
+  @Override
+  public Region getRegion(RegionPosition pos) {
+    return EmptyRegion.instance;
+  }
+
+  @Override
+  public Region getRegionWithinRange(RegionPosition pos, HeightRange heightRange) {
+    return EmptyRegion.instance;
+  }
+
+  @Override
+  public boolean hasRegion(RegionPosition pos) {
+    return false;
   }
 
   @Override
-  public String toString() {
+  public boolean hasRegionWithinRange(RegionPosition pos, HeightRange heightRange) {
+    return false;
+  }
+
+  @Override
+  public HeightRange heightRange() {
+    return new HeightRange(0, 0);
+  }
+
+  @Override public String getName() {
     return "[empty dimension]";
   }
+
+  @Override
+  public boolean reloadPlayerData() {
+    return false;
+  }
+
+  @Override
+  public Optional<Vector3> getPlayerPos() {
+    return Optional.empty();
+  }
 }
diff --git a/chunky/src/java/se/llbit/chunky/world/EmptyRegionChunk.java b/chunky/src/java/se/llbit/chunky/world/EmptyRegionChunk.java
index 029f664585..c4b2f533ca 100644
--- a/chunky/src/java/se/llbit/chunky/world/EmptyRegionChunk.java
+++ b/chunky/src/java/se/llbit/chunky/world/EmptyRegionChunk.java
@@ -23,10 +23,11 @@
 import se.llbit.chunky.ui.ChunkMap;
 import se.llbit.chunky.world.biome.BiomePalette;
 import se.llbit.util.Mutable;
+import se.llbit.util.annotation.NotNull;
 
 /**
  * Empty or non-existent chunk in a region that <b>does not</b> exist.
- * In the {@link ChunkMap map view} an {@link EmptyChunk} is represented as gray.
+ * In the {@link ChunkMap map view} an {@link EmptyRegionChunk} is represented as gray.
  *
  * @author Jesper Öqvist <jesper@llbit.se>
  */
@@ -48,7 +49,7 @@ private EmptyRegionChunk() {
     surface = IconLayer.CORRUPT;
   }
 
-  @Override public synchronized void getChunkData(Mutable<ChunkData> reuseChunkData, BlockPalette palette, BiomePalette biomePalette, int yMin, int yMax) { }
+  @Override public synchronized void getChunkData(@NotNull Mutable<ChunkData> reuseChunkData, BlockPalette palette, BiomePalette biomePalette, int yMin, int yMax) { }
 
   @Override public void renderSurface(MapTile tile) {
     renderEmpty(tile);
@@ -80,7 +81,7 @@ private void renderEmpty(MapTile tile) {
     // do nothing
   }
 
-  @Override public synchronized boolean loadChunk(Mutable<ChunkData> chunkData, int yMin, int yMax) {
+  @Override public synchronized boolean loadChunk(@NotNull Mutable<ChunkData> chunkData, int yMin, int yMax) {
     return false;
   }
 
diff --git a/chunky/src/java/se/llbit/chunky/world/EmptyWorld.java b/chunky/src/java/se/llbit/chunky/world/EmptyWorld.java
index d302150b49..100993cc70 100644
--- a/chunky/src/java/se/llbit/chunky/world/EmptyWorld.java
+++ b/chunky/src/java/se/llbit/chunky/world/EmptyWorld.java
@@ -16,6 +16,14 @@
  */
 package se.llbit.chunky.world;
 
+import se.llbit.chunky.world.worldformat.WorldFormat;
+import se.llbit.util.annotation.NotNull;
+
+import java.nio.file.Path;
+import java.util.Collections;
+import java.util.Optional;
+import java.util.Set;
+
 /**
  * Represents an empty or non-existent world.
  *
@@ -27,18 +35,62 @@ public class EmptyWorld extends World {
   public static final EmptyWorld INSTANCE = new EmptyWorld();
 
   private EmptyWorld() {
-    super("[empty world]", null, 0, -1);
-    this.currentDimension = new EmptyDimension();
+    super(new World.Info("[empty world]", Path.of(""), 0, 0, "Survival",
+        new WorldFormat() {
+          @Override
+          public boolean isValid(@NotNull Path path) {
+            return false;
+          }
+
+          @NotNull
+          @Override
+          public Optional<Info> getWorldInfo(@NotNull Path path) {
+            return Optional.empty();
+          }
+
+          @NotNull
+          @Override
+          public World loadWorld(@NotNull Info info) {
+            return EmptyWorld.INSTANCE;
+          }
+
+          @Override
+          public String getName() {
+            return "Empty World Format";
+          }
+
+          @Override
+          public String getDescription() {
+            return "";
+          }
+
+          @Override
+          public String getId() {
+            return "";
+          }
+        }),
+      new EmptyDimension()
+    );
   }
 
   @Override
-  public void loadDimension(Dimension.Identifier dimensionId) {
+  public Set<Dimension.Identifier> getAvailableDimensions() {
+    return Collections.emptySet();
+  }
+
+  @Override
+  public Optional<Dimension.Identifier> getDefaultDimension() {
+    return Optional.empty();
+  }
+
+  @Override
+  public Dimension loadDimension(Dimension.Identifier dimensionId) {
     // no-op
+    return this.currentDimension;
   }
 
   @Override
   public String toString() {
     return "[empty world]";
   }
-
 }
diff --git a/chunky/src/java/se/llbit/chunky/world/HeightRange.java b/chunky/src/java/se/llbit/chunky/world/HeightRange.java
new file mode 100644
index 0000000000..b1105efedf
--- /dev/null
+++ b/chunky/src/java/se/llbit/chunky/world/HeightRange.java
@@ -0,0 +1,7 @@
+package se.llbit.chunky.world;
+
+/**
+ * @param min Lower (INCLUSIVE) bound of the range
+ * @param max Upper (EXCLUSIVE) bound of the range
+ */
+public record HeightRange(int min, int max) { }
diff --git a/chunky/src/java/se/llbit/chunky/world/ImposterCubicChunk.java b/chunky/src/java/se/llbit/chunky/world/ImposterCubicChunk.java
index 1ea4ed8460..e1e5a1e18c 100644
--- a/chunky/src/java/se/llbit/chunky/world/ImposterCubicChunk.java
+++ b/chunky/src/java/se/llbit/chunky/world/ImposterCubicChunk.java
@@ -9,6 +9,7 @@
 import se.llbit.chunky.world.biome.ArrayBiomePalette;
 import se.llbit.chunky.world.biome.BiomePalette;
 import se.llbit.chunky.world.biome.Biomes;
+import se.llbit.chunky.world.java.JavaChunk;
 import se.llbit.chunky.world.region.ImposterCubicRegion;
 import se.llbit.nbt.CompoundTag;
 import se.llbit.nbt.ListTag;
@@ -26,7 +27,7 @@
  *
  * Represents an infinitely tall column of 16x16x16 Cubes
  */
-public class ImposterCubicChunk extends Chunk {
+public class ImposterCubicChunk extends JavaChunk {
   private final CubicDimension dimension;
 
   public ImposterCubicChunk(ChunkPosition pos, Dimension dimension) {
@@ -52,7 +53,7 @@ private Map<Integer, Map<String, Tag>> getCubeTags(Set<String> request) {
    */
   @Override
   public synchronized boolean loadChunk(@NotNull Mutable<ChunkData> mutableChunkData, int yMin, int yMax) {
-    if (!shouldReloadChunk()) {
+    if (!shouldReload()) {
       return false;
     }
 
diff --git a/chunky/src/java/se/llbit/chunky/world/PlayerEntityData.java b/chunky/src/java/se/llbit/chunky/world/PlayerEntityData.java
index df2ad653ac..493c0c8e97 100644
--- a/chunky/src/java/se/llbit/chunky/world/PlayerEntityData.java
+++ b/chunky/src/java/se/llbit/chunky/world/PlayerEntityData.java
@@ -93,7 +93,7 @@ public PlayerEntityData(Tag player) {
     }
   }
 
-  static UUID getUuid(Tag playerTag) {
+  public static UUID getUuid(Tag playerTag) {
     final UUID uuid;
     long uuidHi;
     long uuidLo;
diff --git a/chunky/src/java/se/llbit/chunky/world/World.java b/chunky/src/java/se/llbit/chunky/world/World.java
index 51653becde..54785870cc 100644
--- a/chunky/src/java/se/llbit/chunky/world/World.java
+++ b/chunky/src/java/se/llbit/chunky/world/World.java
@@ -16,65 +16,50 @@
  */
 package se.llbit.chunky.world;
 
-import se.llbit.log.Log;
-import se.llbit.math.Vector3i;
-import se.llbit.nbt.NamedTag;
-import se.llbit.nbt.Tag;
-import se.llbit.util.MinecraftText;
-import se.llbit.util.UuidUtil;
+import se.llbit.chunky.world.worldformat.WorldFormat;
 import se.llbit.util.annotation.NotNull;
 
 import java.io.*;
 import java.nio.file.Path;
 import java.util.*;
-import java.util.stream.Collectors;
-import java.util.zip.GZIPInputStream;
 
 /**
- * The World class contains information about the currently viewed world.
- * It has a map of all chunks in the world and is responsible for parsing
- * chunks when needed. All rendering is done through the WorldRenderer class.
+ * The World class contains {@link Info metadata} about itself, and methods for querying and loading its dimensions.
+ * It also contains the {@link #currentDimension() currently loaded dimension} if there is one.
  *
  * @author Jesper Öqvist <jesper@llbit.se>
  */
-public class World implements Comparable<World> {
-
-  /** The currently supported NBT version of level.dat files. */
-  public static final int NBT_VERSION = 19133;
+public abstract class World {
+  /**
+   * Metadata about a world.
+   */
+  public record Info(String name, Path path, long lastModified, long seed, String gameMode, WorldFormat worldFormat) {
+    /**
+     * Chunky sees each valid {@link Info#path()} and {@link Info#worldFormat()} combination as a distinct world which
+     * can be selected by the user.
+     */
+    public boolean isSameWorld(Info other) {
+      return this.worldFormat == other.worldFormat && this.path.equals(other.path);
+    }
+  }
 
   /** Default sea water level. */
   public static final int SEA_LEVEL = 63;
 
-  /** Minimum level.dat data version of tall worlds (21w06a). */
-  public static final int VERSION_21W06A = 2694;
-  public static final int VERSION_1_12_2 = 1343;
-
-  private final File worldDirectory;
+  private final Info info;
 
+  @NotNull
   protected Dimension currentDimension;
 
-  private final String levelName;
-  private int gameMode = 0;
-  private final long seed;
-
-  private int versionId;
-
-  /** Timestamp for level.dat when player data was last loaded. */
-  private long timestamp;
-
-  private UUID singleplayerPlayerUuid;
+  protected World(Info info) {
+    this.info = info;
+    this.currentDimension = EmptyWorld.INSTANCE.currentDimension();
+  }
 
-  /**
-   * @param levelName name of the world (not the world directory).
-   * @param worldDirectory Minecraft world directory.
-   * @param seed
-   * @param timestamp
-   */
-  protected World(String levelName, File worldDirectory, long seed, long timestamp) {
-    this.levelName = levelName;
-    this.worldDirectory = worldDirectory;
-    this.seed = seed;
-    this.timestamp = timestamp;
+  /** Only for use by {@link EmptyWorld} */
+  protected World(Info info, @NotNull EmptyDimension dimension) {
+    this.info = info;
+    this.currentDimension = dimension;
   }
 
   public enum LoggedWarnings {
@@ -82,246 +67,40 @@ public enum LoggedWarnings {
     SILENT
   }
 
-  public void loadDimension(Dimension.Identifier dimensionId) {
-    currentDimension = loadDimension(this, this.worldDirectory, dimensionId, Collections.emptySet());
-    currentDimension.reloadPlayerData();
-  }
-
   /**
-   * Parse player location and level name.
+   * The dimensions returned here are later provided to {@link #loadDimension(Dimension.Identifier)} when requesting a
+   * dimension be loaded.
    *
-   * @return {@code true} if the world data was loaded
+   * @return List the viewable dimensions within the world.
    */
-  public static World loadWorld(File worldDirectory, Dimension.Identifier dimensionId, LoggedWarnings warnings) {
-    if (worldDirectory == null) {
-      return EmptyWorld.INSTANCE;
-    }
-    String levelName = worldDirectory.getName(); // Default level name.
-    File worldFile = new File(worldDirectory, "level.dat");
-    long modtime = worldFile.lastModified();
-    try (FileInputStream fin = new FileInputStream(worldFile);
-        InputStream gzin = new GZIPInputStream(fin);
-        DataInputStream in = new DataInputStream(gzin)) {
-      Set<String> request = new HashSet<>();
-      request.add(".Data.version");
-      request.add(".Data.Version.Id");
-      request.add(".Data.RandomSeed");
-      request.add(".Data.Player");
-      request.add(".Data.singleplayer_uuid");
-      request.add(".Data.LevelName");
-      request.add(".Data.GameType");
-      request.add(".Data.isCubicWorld");
-      Map<String, Tag> result = NamedTag.quickParse(in, request);
-
-      Tag version = result.get(".Data.version");
-      if (warnings == LoggedWarnings.NORMAL && version.intValue() != NBT_VERSION) {
-        Log.warnf("The world format for the world %s is not supported by Chunky.\n" + "Will attempt to load the world anyway.",
-            levelName);
-      }
-      Tag versionId = result.get(".Data.Version.Id");
-      Tag player = result.get(".Data.Player");
-      Tag spawnX = player.get("SpawnX");
-      Tag spawnY = player.get("SpawnY");
-      Tag spawnZ = player.get("SpawnZ");
-      Tag singleplayerUuid = result.get(".Data.singleplayer_uuid");
-      Tag gameType = result.get(".Data.GameType");
-      Tag randomSeed = result.get(".Data.RandomSeed");
-      levelName = MinecraftText.removeFormatChars(result.get(".Data.LevelName").stringValue(levelName));
-
-      long seed = randomSeed.longValue(0);
-
-      Set<PlayerEntityData> playerEntities = getPlayerEntityData(worldDirectory, dimensionId, player);
-
-      World world = new World(levelName, worldDirectory, seed, modtime);
-      world.gameMode = gameType.intValue(0);
-      world.versionId = versionId.intValue();
-      if (singleplayerUuid.isIntArray(4)) {
-        world.singleplayerPlayerUuid = UuidUtil.intsToUuid(singleplayerUuid.intArray());
-      } else if (!player.isError()) {
-        world.singleplayerPlayerUuid = PlayerEntityData.getUuid(player);
-      }
-
-      Dimension dimension = loadDimension(world, worldDirectory, dimensionId, playerEntities);
-
-      boolean haveSpawnPos = !(spawnX.isError() || spawnY.isError() || spawnZ.isError());
-      if (haveSpawnPos) {
-        dimension.setSpawnPos(new Vector3i(spawnX.intValue(0), spawnY.intValue(0), spawnZ.intValue(0)));
-      }
-
-      world.currentDimension = dimension;
-
-      return world;
-    } catch (FileNotFoundException e) {
-      if (warnings == LoggedWarnings.NORMAL) {
-        Log.infof("Could not find level.dat file for world %s!", levelName);
-      }
-    } catch (IOException e) {
-      if (warnings == LoggedWarnings.NORMAL) {
-        Log.infof("Could not read the level.dat file for world %s!", levelName);
-      }
-    }
-    return EmptyWorld.INSTANCE;
-  }
-
-  @NotNull
-  private static Dimension loadDimension(World world, File worldDirectory, Dimension.Identifier dimensionId, Set<PlayerEntityData> playerEntities) {
-    File dimensionDirectory = Path.of(worldDirectory.getPath(), "dimensions", dimensionId.namespace(), dimensionId.name()).toFile();
-    if (dimensionDirectory.exists()) {
-      // 26.1-snapshot-6 or later
-      return new Dimension(world, dimensionId, dimensionDirectory, playerEntities);
-    }
-
-    dimensionDirectory = switch (dimensionId.getNamespacedName()) { // TODO in Java 21+ we can use `switch (dimensionId)` here
-      case "minecraft:the_nether" -> new File(worldDirectory, "DIM-1");
-      case "minecraft:the_end" -> new File(worldDirectory, "DIM1");
-      default -> worldDirectory;
-    };
-    if (new File(dimensionDirectory, "region3d").exists()) {
-      return new CubicDimension(world, dimensionId, dimensionDirectory, playerEntities);
-    } else {
-      return new Dimension(world, dimensionId, dimensionDirectory, playerEntities);
-    }
-  }
-
-  @NotNull
-  private static Set<PlayerEntityData> getPlayerEntityData(File worldDirectory, Dimension.Identifier dimensionId, Tag player) {
-    Set<PlayerEntityData> playerEntities = new HashSet<>();
-    if (!player.isError()) {
-      playerEntities.add(new PlayerEntityData(player));
-    }
-    loadAdditionalPlayers(worldDirectory, playerEntities);
-    // Filter for the players only within the requested dimension
-    playerEntities = playerEntities.stream().filter(playerData -> playerData.dimension.equals(dimensionId)).collect(Collectors.toSet());
-    return playerEntities;
-  }
+  public abstract Set<Dimension.Identifier> getAvailableDimensions();
 
   /**
-   * Reload player data for the current dimension. This method is not in Dimension because players are per-world, not per-dimension
-   * @return {@code true} if player data was reloaded.
+   * <b>MUST</b> be one of {@link #getAvailableDimensions()}
+   * @return The preferred default dimension of this world (typically the overworld)
    */
-  synchronized boolean reloadPlayerData() {
-    if (worldDirectory == null) {
-      return false;
-    }
-    File worldFile = new File(worldDirectory, "level.dat");
-    long lastModified = worldFile.lastModified();
-    if (lastModified == timestamp) {
-      return false;
-    }
-    Log.infof("world %s: timestamp updated: reading player data", levelName);
-    timestamp = lastModified;
-
-    try (FileInputStream fin = new FileInputStream(worldFile);
-         InputStream gzin = new GZIPInputStream(fin);
-         DataInputStream in = new DataInputStream(gzin)) {
-      Set<String> request = new HashSet<>();
-      request.add(".Data.Player");
-      request.add(".Data.singleplayer_uuid");
-      Map<String, Tag> result = NamedTag.quickParse(in, request);
-      Tag player = result.get(".Data.Player");
-      Tag singleplayerUuid = result.get(".Data.singleplayer_uuid");
-      if (singleplayerUuid.isIntArray(4)) {
-        singleplayerPlayerUuid = UuidUtil.intsToUuid(singleplayerUuid.intArray());
-      } else if (!player.isError()) {
-        singleplayerPlayerUuid = PlayerEntityData.getUuid(player);
-      }
-
-      currentDimension.setPlayerEntities(getPlayerEntityData(worldDirectory, currentDimension.getDimensionId(), player));
-    } catch (IOException e) {
-      Log.infof("Could not read the level.dat file for world %s while trying to reload player data!", levelName);
-      return false;
-    }
-    return true;
-  }
-
-  private static void loadAdditionalPlayers(File worldDirectory, Set<PlayerEntityData> playerEntities) {
-    loadPlayerData(new File(worldDirectory, "players"), playerEntities);
-    loadPlayerData(new File(worldDirectory, "playerdata"), playerEntities);
-    loadPlayerData(new File(new File(worldDirectory, "players"), "data"), playerEntities); // 26.1-snapshot-6 or later
-  }
+  public abstract Optional<Dimension.Identifier> getDefaultDimension();
 
-  private static void loadPlayerData(File playerdata, Set<PlayerEntityData> playerEntities) {
-    if (playerdata.isDirectory()) {
-      File[] players = playerdata.listFiles();
-      if (players != null) {
-        for (File player : players) {
-          try (DataInputStream in = new DataInputStream(
-              new GZIPInputStream(new FileInputStream(player)))) {
-            playerEntities.add(new PlayerEntityData(NamedTag.read(in).unpack()));
-          } catch (IOException e) {
-            Log.infof("Could not read player data file '%s'", player.getAbsolutePath());
-          }
-        }
-      }
-    }
-  }
+  /**
+   * @param dimensionId The dimension to load, guaranteed to be one of the dimensions previously returned by {@link #getAvailableDimensions()}
+   * @return The loaded dimension
+   */
+  public abstract Dimension loadDimension(Dimension.Identifier dimensionId);
 
   /**
-   * @return The current dimension
+   * @return The current dimension or {@link EmptyDimension#INSTANCE} if there isn't one.
    */
+  @NotNull
   public synchronized Dimension currentDimension() {
     return this.currentDimension;
   }
 
-  public Optional<UUID> getSingleplayerPlayerUuid() {
-    return Optional.ofNullable(singleplayerPlayerUuid);
-  }
-
-  /**
-   * @return The world directory
-   */
-  public File getWorldDirectory() {
-    return worldDirectory;
+  public Info getInfo() {
+    return this.info;
   }
 
   @Override public String toString() {
-    return levelName + " (" + worldDirectory.getName() + ")";
-  }
-
-  /** The name of this world (not the world directory name). */
-  public String levelName() {
-    return levelName;
-  }
-
-  public int getVersionId() {
-    return versionId;
-  }
-
-  /**
-   * @return <code>true</code> if the given directory exists and
-   * contains a level.dat file
-   */
-  public static boolean isWorldDir(File worldDir) {
-    if (worldDir != null && worldDir.isDirectory()) {
-      File levelDat = new File(worldDir, "level.dat");
-      return levelDat.exists() && levelDat.isFile();
-    }
-    return false;
-  }
-
-  /**
-   * @return String describing the game-mode of this world
-   */
-  public String gameMode() {
-    return switch (gameMode) {
-      case 0 -> "Survival";
-      case 1 -> "Creative";
-      case 2 -> "Adventure";
-      default -> "Unknown";
-    };
-  }
-
-  @Override public int compareTo(World o) {
-    // Compares world names and directories.
-    return toString().compareToIgnoreCase(o.toString());
-  }
-
-  public long getSeed() {
-    return seed;
-  }
-
-  public Date getLastModified() {
-    return new Date(this.worldDirectory.lastModified());
+    return info.name + " (" + info.path.getFileName() + ")";
   }
 
   /**
@@ -330,7 +109,7 @@ public Date getLastModified() {
    * @return Resource pack file/directory or empty optional if this world has no bundled resource pack
    */
   public Optional<File> getResourcePack() {
-    for (File resourcepacksDirectory : new File[]{getWorldDirectory(), new File(getWorldDirectory(), "resourcepacks")}) {
+    for (File resourcepacksDirectory : new File[]{ info.path.toFile(), new File(info.path.toFile(), "resourcepacks")}) {
       if (resourcepacksDirectory.isDirectory()) {
         File resourcePack = new File(resourcepacksDirectory, "resources.zip");
     if (resourcePack.isFile()) {
diff --git a/chunky/src/java/se/llbit/chunky/world/java/JavaChunk.java b/chunky/src/java/se/llbit/chunky/world/java/JavaChunk.java
new file mode 100644
index 0000000000..c662f912e7
--- /dev/null
+++ b/chunky/src/java/se/llbit/chunky/world/java/JavaChunk.java
@@ -0,0 +1,364 @@
+package se.llbit.chunky.world.java;
+
+import se.llbit.chunky.block.legacy.LegacyBlocks;
+import se.llbit.chunky.chunk.BlockPalette;
+import se.llbit.chunky.chunk.ChunkData;
+import se.llbit.chunky.chunk.ChunkLoadingException;
+import se.llbit.chunky.chunk.EmptyChunkData;
+import se.llbit.chunky.chunk.biome.BiomeDataFactory;
+import se.llbit.chunky.map.BiomeLayer;
+import se.llbit.chunky.map.IconLayer;
+import se.llbit.chunky.map.SurfaceLayer;
+import se.llbit.chunky.world.*;
+import se.llbit.chunky.world.biome.ArrayBiomePalette;
+import se.llbit.chunky.world.biome.BiomePalette;
+import se.llbit.chunky.world.java.region.JavaRegion;
+import se.llbit.chunky.world.region.Region;
+import se.llbit.log.Log;
+import se.llbit.math.QuickMath;
+import se.llbit.nbt.CompoundTag;
+import se.llbit.nbt.ListTag;
+import se.llbit.nbt.SpecificTag;
+import se.llbit.nbt.Tag;
+import se.llbit.util.BitBuffer;
+import se.llbit.util.Mutable;
+import se.llbit.util.annotation.NotNull;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import static se.llbit.util.NbtUtil.getTagFromNames;
+import static se.llbit.util.NbtUtil.tagFromMap;
+
+public class JavaChunk extends Chunk {
+  public JavaChunk(ChunkPosition pos, Dimension dimension) {
+    super(pos, dimension);
+  }
+
+  /**
+   * @param request fresh request set
+   * @return loaded data, or null if something went wrong
+   */
+  private Map<String, Tag> getChunkTags(Set<String> request) throws ChunkLoadingException {
+    JavaRegion region = (JavaRegion) dimension.getRegion(position.getRegionPosition());
+    Mutable<Integer> timestamp = new Mutable<>(dataTimestamp);
+    Map<String, Tag> chunkTags = region.getChunkTags(this.position, request, timestamp);
+    this.dataTimestamp = timestamp.get();
+    return chunkTags;
+  }
+
+  /**
+   * @param request fresh request set
+   * @return loaded data, or null if something went wrong
+   */
+  private Map<String, Tag> getEntityTags(Set<String> request) throws ChunkLoadingException {
+    JavaRegion region = (JavaRegion) dimension.getRegion(position.getRegionPosition());
+    return region.getEntityTags(this.position, request);
+  }
+
+  @Override
+  public synchronized boolean loadChunk(@NotNull Mutable<ChunkData> chunkData, int yMin, int yMax) {
+    if (!shouldReload()) {
+      return false;
+    }
+
+    Set<String> request = new HashSet<>();
+    request.add(Chunk.DATAVERSION);
+    request.add(Chunk.LEVEL_SECTIONS);
+    request.add(Chunk.SECTIONS_POST_21W39A);
+    request.add(Chunk.LEVEL_BIOMES);
+    request.add(Chunk.BIOMES_POST_21W39A);
+    request.add(Chunk.LEVEL_HEIGHTMAP);
+
+    Map<String, Tag> dataMap;
+    try {
+      dataMap = getChunkTags(request);
+    } catch (ChunkLoadingException e) { // we don't want to crash the map view if a chunk fails to load, so we warn the user
+      Log.warn(String.format("Failed to load chunk %s", position), e);
+      return false;
+    }
+    // TODO: improve error handling here.
+    if (dataMap == null) {
+      return false;
+    }
+    Tag data = tagFromMap(dataMap);
+
+    surfaceTimestamp = dataTimestamp;
+    version = getChunkVersion(data);
+    HeightRange chunkBounds = inclusiveChunkBounds(data);
+    chunkData.set(this.dimension.createChunkData(chunkData.get(), chunkBounds.min(), chunkBounds.max()));
+    loadSurface(data, chunkData.get(), yMin, yMax);
+    biomesTimestamp = dataTimestamp;
+
+    dimension.chunkUpdated(position);
+    return true;
+  }
+
+  private void loadSurface(@NotNull Tag data, ChunkData chunkData, int yMin, int yMax) {
+    if (data == null) {
+      surface = IconLayer.CORRUPT;
+      return;
+    }
+
+    Heightmap heightmap = dimension.getHeightmap();
+    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
+    if (sections.isList()) {
+      if (version == ChunkVersion.PRE_FLATTENING || version == ChunkVersion.POST_FLATTENING) {
+        BiomePalette biomePalette = new ArrayBiomePalette();
+        BiomeDataFactory.loadBiomeData(chunkData, data, biomePalette, yMin, yMax);
+        biomes = new BiomeLayer(chunkData, biomePalette);
+
+        BlockPalette palette = new BlockPalette();
+        palette.unsynchronize(); //only this RegionParser will use this palette
+        loadBlockData(data, chunkData, palette, yMin, yMax);
+
+        int[] heightmapData = extractHeightmapData(data, chunkData);
+        updateHeightmap(heightmap, position, chunkData, heightmapData, palette, yMax);
+
+        surface = new SurfaceLayer(dimension.getDimensionId(), chunkData, palette, biomePalette, yMin, yMax, heightmapData);
+        queueTopography();
+      }
+    } else {
+      surface = IconLayer.CORRUPT;
+    }
+  }
+
+  private int[] extractHeightmapData(@NotNull Tag data, ChunkData chunkData) {
+    Tag heightmapTag = data.get(LEVEL_HEIGHTMAP);
+    if (heightmapTag.isIntArray(X_MAX * Z_MAX)) {
+      return heightmapTag.intArray();
+    } else {
+      int[] fallback = new int[X_MAX * Z_MAX];
+      for (int i = 0; i < fallback.length; ++i) {
+        fallback[i] = chunkData.maxY();
+      }
+      return fallback;
+    }
+  }
+
+  protected boolean shouldReload() {
+    int timestamp = Integer.MAX_VALUE;
+    timestamp = Math.min(timestamp, surfaceTimestamp);
+    timestamp = Math.min(timestamp, biomesTimestamp);
+    if (timestamp == 0) {
+      return true;
+    }
+    Region region = dimension.getRegion(position.getRegionPosition());
+    return region.chunkChangedSince(position, timestamp);
+  }
+
+  /** Detect Minecraft version that generated the chunk. */
+  private static ChunkVersion getChunkVersion(@NotNull Tag data) {
+    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
+    if (sections.isList()) {
+      for (SpecificTag section : sections.asList()) {
+        if (!section.get("Palette").isList()) {
+          if (section.get("Blocks").isByteArray(SECTION_BYTES)) {
+            return ChunkVersion.PRE_FLATTENING;
+          }
+        }
+      }
+      return ChunkVersion.POST_FLATTENING;
+    }
+    return ChunkVersion.UNKNOWN;
+  }
+
+  private static void loadBlockData(@NotNull Tag data, @NotNull ChunkData chunkData,
+                                    BlockPalette blockPalette, int minY, int maxY) {
+
+    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
+    if (sections.isList()) {
+      for (SpecificTag section : sections.asList()) {
+        Tag yTag = section.get("Y");
+        int sectionY = yTag.byteValue();
+        int sectionMinBlockY = sectionY << 4;
+
+        if(sectionY < minY >> 4 || sectionY-1 > (maxY >> 4)+1)
+          continue; //skip parsing sections that are outside requested bounds
+
+        Tag blockPaletteTag = getTagFromNames(section, "Palette", "block_states\\palette");
+        if (blockPaletteTag.isList()) {
+          ListTag localBlockPalette = blockPaletteTag.asList();
+          // Bits per block:
+          int bpb = 4;
+          if (localBlockPalette.size() > 16) {
+            bpb = QuickMath.log2(QuickMath.nextPow2(localBlockPalette.size()));
+          }
+
+          int dataSize = (4096 * bpb) / 64;
+          Tag blockStates = getTagFromNames(section, "BlockStates", "block_states\\data");
+
+          if (blockStates.isLongArray(dataSize)) {
+            // since 20w17a, block states are aligned to 64-bit boundaries, so there are 64 % bpb
+            // unused bits per block state; if so, the array is longer than the expected data size
+            boolean isAligned = data.get(DATAVERSION).intValue() >= DATAVERSION_20W17A;
+            if (isAligned) {
+              // entries are 64-bit-padded, re-calculate the bits per block
+              // this is the dataSize calculation from above reverted, we know the actual data size
+              bpb = blockStates.longArray().length / 64;
+            }
+
+            int[] subpalette = new int[localBlockPalette.size()];
+            int paletteIndex = 0;
+            for (Tag item : localBlockPalette.asList()) {
+              subpalette[paletteIndex] = blockPalette.put(item);
+              paletteIndex += 1;
+            }
+            BitBuffer buffer = new BitBuffer(blockStates.longArray(), bpb, isAligned);
+            for (int y = 0; y < SECTION_Y_MAX; y++) {
+              int blockY = sectionMinBlockY + y;
+              for (int z = 0; z < Z_MAX; z++) {
+                for(int x = 0; x < X_MAX; x++) {
+                  int b0 = buffer.read();
+                  if (b0 < subpalette.length) {
+                    chunkData.setBlockAt(x, blockY, z, subpalette[b0]);
+                  }
+                }
+              }
+            }
+          } else {
+            // Single block palette
+            if (localBlockPalette.size() == 1) {
+              // Check it is not air block
+              int block = blockPalette.put(localBlockPalette.get(0));
+              if (block != blockPalette.airId) {
+                // Set the entire section
+                for (int y = 0; y < SECTION_Y_MAX; y++) {
+                  int blockY = sectionMinBlockY + y;
+                  for (int z = 0; z < Z_MAX; z++) {
+                    for(int x = 0; x < X_MAX; x++) {
+                      chunkData.setBlockAt(x, blockY, z, block);
+                    }
+                  }
+                }
+              }
+            }
+          }
+        } else {
+          int yOffset = sectionY & 0xFF;
+
+          Tag dataTag = section.get("Data");
+          byte[] blockDataBytes = new byte[(Chunk.X_MAX * Chunk.Y_MAX * Chunk.Z_MAX) / 2];
+          if (dataTag.isByteArray(SECTION_HALF_NIBBLES)) {
+            System.arraycopy(dataTag.byteArray(), 0, blockDataBytes, SECTION_HALF_NIBBLES * yOffset,
+              SECTION_HALF_NIBBLES);
+          }
+
+          Tag blocksTag = section.get("Blocks");
+          if (blocksTag.isByteArray(SECTION_BYTES)) {
+            byte[] blocksBytes = new byte[Chunk.X_MAX * Chunk.Y_MAX * Chunk.Z_MAX];
+            System.arraycopy(blocksTag.byteArray(), 0, blocksBytes, SECTION_BYTES * yOffset,
+              SECTION_BYTES);
+
+            int offset = SECTION_BYTES * yOffset;
+            for (int y = 0; y < SECTION_Y_MAX; y++) {
+              int blockY = sectionMinBlockY + y;
+              for (int z = 0; z < Z_MAX; z++) {
+                for (int x = 0; x < X_MAX; x++) {
+                  chunkData.setBlockAt(x, blockY, z, blockPalette.put(
+                    LegacyBlocks.getTag(offset, blocksBytes, blockDataBytes)));
+                  offset += 1;
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  @Override
+  public synchronized void getChunkData(@NotNull Mutable<ChunkData> reuseChunkData, BlockPalette palette, BiomePalette biomePalette, int minY, int maxY) throws ChunkLoadingException {
+    Set<String> request = new HashSet<>();
+    request.add(DATAVERSION);
+    request.add(LEVEL_SECTIONS);
+    request.add(SECTIONS_POST_21W39A);
+    request.add(LEVEL_BIOMES);
+    request.add(BIOMES_POST_21W39A);
+    request.add(LEVEL_ENTITIES);
+    request.add(LEVEL_TILEENTITIES);
+    request.add(BLOCK_ENTITIES_POST_21W43A);
+    Map<String, Tag> dataMap = getChunkTags(request);
+    // TODO: improve error handling here.
+    if (dataMap == null) {
+      throw new ChunkLoadingException(String.format("Got null data for chunk %s", this.position));
+    }
+    Tag data = tagFromMap(dataMap);
+
+    int dataVersion = data.get(DATAVERSION).intValue();
+
+    HeightRange chunkBounds = inclusiveChunkBounds(data);
+
+    if(reuseChunkData.get() == null || reuseChunkData.get() instanceof EmptyChunkData) {
+      reuseChunkData.set(dimension.createChunkData(reuseChunkData.get(), chunkBounds.min(), chunkBounds.max()));
+    } else {
+      reuseChunkData.get().clear();
+    }
+    ChunkData chunkData = reuseChunkData.get(); //unwrap mutable, for ease of use
+
+    version = getChunkVersion(data);
+    Tag sections = getTagFromNames(data, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
+    Tag entitiesTag = data.get(LEVEL_ENTITIES);
+    Tag tileEntitiesTag = getTagFromNames(data, LEVEL_TILEENTITIES, BLOCK_ENTITIES_POST_21W43A);
+
+    BiomeDataFactory.loadBiomeData(chunkData, data, biomePalette, minY, maxY);
+    if (sections.isList()) {
+      loadBlockData(data, chunkData, palette, minY, maxY);
+
+      if (entitiesTag.isList()) {
+        for (SpecificTag tag : (ListTag) entitiesTag) {
+          if (tag.isCompoundTag())
+            chunkData.addEntity((CompoundTag) tag);
+        }
+      }
+
+      if (tileEntitiesTag.isList()) {
+        for (SpecificTag tag : (ListTag) tileEntitiesTag) {
+          if (tag.isCompoundTag())
+            chunkData.addTileEntity((CompoundTag) tag);
+        }
+      }
+    }
+
+    // post 20w45A entities
+    if (dataVersion >= DATAVERSION_20W45A) {
+      Set<String> entitiesRequest = new HashSet<>();
+      entitiesRequest.add(ENTITIES_POST_20W45A);
+
+      Map<String, Tag> entitiesMap = getEntityTags(entitiesRequest);
+      if (entitiesMap != null) {
+        entitiesTag = entitiesMap.get(".Entities");
+        if (entitiesTag.isList()) {
+          for (SpecificTag tag : (ListTag) entitiesTag) {
+            if (tag.isCompoundTag())
+              chunkData.addEntity((CompoundTag) tag);
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * @return The min and max blockY for a given section array
+   */
+  private HeightRange inclusiveChunkBounds(Tag chunkData) {
+    Tag sections = getTagFromNames(chunkData, LEVEL_SECTIONS, SECTIONS_POST_21W39A);
+    int minSectionY = Integer.MAX_VALUE;
+    int maxSectionY = Integer.MIN_VALUE;
+    if (sections.isList()) {
+      for (SpecificTag section : sections.asList()) {
+        byte sectionY = (byte) section.get("Y").byteValue();
+        if (sectionY < minSectionY) {
+          minSectionY = sectionY;
+        }
+        if (sectionY > maxSectionY) {
+          maxSectionY = sectionY;
+        }
+      }
+    }
+
+    return new HeightRange(minSectionY << 4, (maxSectionY << 4) + 15);
+  }
+
+}
diff --git a/chunky/src/java/se/llbit/chunky/world/java/JavaDimension.java b/chunky/src/java/se/llbit/chunky/world/java/JavaDimension.java
new file mode 100644
index 0000000000..dcfb177990
--- /dev/null
+++ b/chunky/src/java/se/llbit/chunky/world/java/JavaDimension.java
@@ -0,0 +1,139 @@
+package se.llbit.chunky.world.java;
+
+import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
+import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
+import se.llbit.chunky.map.MapView;
+import se.llbit.chunky.map.WorldMapLoader;
+import se.llbit.chunky.world.*;
+import se.llbit.chunky.world.java.region.JavaRegion;
+import se.llbit.chunky.world.java.region.JavaRegionChangeWatcher;
+import se.llbit.chunky.world.region.*;
+import se.llbit.math.Vector3;
+import se.llbit.math.Vector3i;
+import se.llbit.util.annotation.Nullable;
+
+import java.io.File;
+import java.nio.file.Path;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+public class JavaDimension extends Dimension {
+  protected final JavaWorld world;
+  protected final Long2ObjectMap<Region> regionMap = new Long2ObjectOpenHashMap<>();
+
+  /**
+   * @param world
+   * @param dimensionId
+   * @param dimensionDirectory Minecraft world directory.
+   * @param playerEntities
+   */
+  protected JavaDimension(JavaWorld world, Identifier dimensionId, Path dimensionDirectory, Set<PlayerEntityData> playerEntities, @Nullable Vector3i spawnPos) {
+    super(dimensionId, dimensionDirectory, playerEntities, spawnPos);
+    this.world = world;
+  }
+
+  @Override
+  public RegionChangeWatcher createRegionChangeWatcher(WorldMapLoader worldMapLoader, MapView mapView) {
+    return new JavaRegionChangeWatcher(worldMapLoader, mapView);
+  }
+
+  @Override
+  public Region createRegion(RegionPosition pos) {
+    return new JavaRegion(pos, this);
+  }
+
+  /**
+   * Set the region for the given position.
+   */
+  public synchronized void setRegion(RegionPosition pos, Region region) {
+    regionMap.put(pos.getLong(), region);
+  }
+
+  @Override
+  public synchronized Region getRegion(RegionPosition pos) {
+    return regionMap.computeIfAbsent(pos.getLong(), p -> {
+      // check if the region is present in the world directory
+      Region region = EmptyRegion.instance;
+      if (hasRegion(pos)) {
+        region = createRegion(pos);
+      }
+      return region;
+    });
+  }
+
+  @Override
+  public Region getRegionWithinRange(RegionPosition pos, HeightRange heightRange) {
+    return getRegion(pos);
+  }
+
+  @Override
+  public boolean hasRegion(RegionPosition pos) {
+    File regionFile = new File(getRegionDirectory(), pos.getMcaName());
+    return regionFile.exists();
+  }
+
+  @Override
+  public boolean hasRegionWithinRange(RegionPosition pos, HeightRange heightRange) {
+    return this.hasRegion(pos);
+  }
+
+  @Override
+  public HeightRange heightRange() {
+    return this.world.versionId >= JavaWorld.VERSION_21W06A ?
+      new HeightRange(-64, 320) :
+      new HeightRange(0, 256);
+  }
+
+
+  @Override
+  public synchronized Chunk getChunk(ChunkPosition pos) {
+    return getRegion(pos.getRegionPosition()).getChunk(pos);
+  }
+
+  @Override
+  public synchronized boolean reloadPlayerData() {
+    boolean changed = this.world.reloadPlayerData();
+    if (changed) {
+      this.playerEntities.clear();
+      this.playerEntities.addAll(this.world.playerEntities.stream()
+        .filter(player -> player.dimension.equals(this.dimensionId))
+        .collect(Collectors.toSet()));
+    }
+    return changed;
+  }
+
+  @Override
+  public synchronized Optional<Vector3> getPlayerPos() {
+    if (!this.playerEntities.isEmpty()) {
+      return world.getSingleplayerPlayerUuid()
+        .flatMap(uuid -> this.playerEntities.stream()
+          .filter(player -> player.uuid.equals(uuid))
+          .map(pos -> new Vector3(pos.x, pos.y, pos.z))
+          .findFirst());
+    } else {
+      return Optional.empty();
+    }
+  }
+
+  /**
+   * Called when a new region has been discovered by the region parser.
+   */
+  public void regionDiscovered(RegionPosition pos) {
+    synchronized (this) {
+      regionMap.computeIfAbsent(pos.getLong(), p -> createRegion(pos));
+    }
+  }
+
+  /**
+   * @return File object pointing to the region file directory
+   */
+  public synchronized File getRegionDirectory() {
+    return dimensionDirectory.resolve("region").toFile();
+  }
+
+  @Override
+  public String getName() {
+    return dimensionDirectory.getFileName().toString();
+  }
+}
diff --git a/chunky/src/java/se/llbit/chunky/world/java/JavaWorld.java b/chunky/src/java/se/llbit/chunky/world/java/JavaWorld.java
new file mode 100644
index 0000000000..de0fe246fd
--- /dev/null
+++ b/chunky/src/java/se/llbit/chunky/world/java/JavaWorld.java
@@ -0,0 +1,265 @@
+package se.llbit.chunky.world.java;
+
+import se.llbit.chunky.world.*;
+import se.llbit.log.Log;
+import se.llbit.math.Vector3i;
+import se.llbit.nbt.NamedTag;
+import se.llbit.nbt.Tag;
+import se.llbit.util.MinecraftText;
+import se.llbit.util.UuidUtil;
+import se.llbit.util.annotation.NotNull;
+import se.llbit.util.annotation.Nullable;
+
+import java.io.*;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.zip.GZIPInputStream;
+
+public class JavaWorld extends World {
+  /** The currently supported NBT version of level.dat files. */
+  public static final int NBT_VERSION = 19133;
+
+  /** Minimum level.dat data version of tall worlds (21w06a). */
+  public static final int VERSION_21W06A = 2694;
+  public static final int VERSION_1_12_2 = 1343;
+
+  protected final int versionId;
+
+  /**
+   * In a java world spawn position is per-world and not per-dimension, so we store it here.
+   */
+  protected final Vector3i spawnPos;
+
+  /**
+   * In a java world player data is per-world and not per-dimension, so we store it here.
+   */
+  protected final Collection<PlayerEntityData> playerEntities;
+
+  protected UUID singleplayerPlayerUuid;
+
+  /** Timestamp of when player data was last loaded. */
+  protected long playerDataTimestamp;
+
+  protected JavaWorld(Info info, long timestamp, int versionId, Set<PlayerEntityData> playerEntities, Vector3i spawnPos) {
+    super(info);
+    this.versionId = versionId;
+    this.playerEntities = playerEntities;
+    this.spawnPos = spawnPos;
+    this.playerDataTimestamp = timestamp;
+  }
+
+  public static Optional<World.Info> loadWorldInfo(@NotNull Path worldDirectory, LoggedWarnings warnings, JavaWorldFormat format) {
+    return readWorldData(worldDirectory, warnings, data -> {
+      Tag gameType = data.tags.get(".Data.GameType");
+      String gameMode = switch (gameType.intValue(0)) {
+        case 0 -> "Survival";
+        case 1 -> "Creative";
+        case 2 -> "Adventure";
+        default -> "Unknown";
+      };
+      Tag randomSeed = data.tags.get(".Data.RandomSeed");
+
+      String levelName = MinecraftText.removeFormatChars(data.tags.get(".Data.LevelName").stringValue(data.levelName));
+
+      long seed = randomSeed.longValue(0);
+
+      return new Info(levelName, worldDirectory, data.modTime, seed, gameMode, format);
+    });
+  }
+
+  public static World loadWorld(Info info, LoggedWarnings warnings) {
+    return readWorldData(info.path(), warnings, data -> {
+      Tag versionId = data.tags.get(".Data.Version.Id");
+
+      Tag player = data.tags.get(".Data.Player");
+      Set<PlayerEntityData> playerEntities = getPlayerEntityData(info.path(), player);
+
+      Tag spawnX = player.get("SpawnX");
+      Tag spawnY = player.get("SpawnY");
+      Tag spawnZ = player.get("SpawnZ");
+      boolean hasSpawnPos = !(spawnX.isError() || spawnY.isError() || spawnZ.isError());
+      Vector3i spawnPos = new Vector3i();
+      if (hasSpawnPos) {
+        spawnPos = new Vector3i(spawnX.intValue(0), spawnY.intValue(0), spawnZ.intValue(0));
+      }
+
+      JavaWorld world = new JavaWorld(info, data.modTime, versionId.intValue(), playerEntities, spawnPos);
+
+      Tag singleplayerUuid = data.tags.get(".Data.singleplayer_uuid");
+      if (singleplayerUuid.isIntArray(4)) {
+        world.singleplayerPlayerUuid = UuidUtil.intsToUuid(singleplayerUuid.intArray());
+      } else if (!player.isError()) {
+        world.singleplayerPlayerUuid = PlayerEntityData.getUuid(player);
+      }
+
+      return (World) world;
+    }).orElse(EmptyWorld.INSTANCE);
+  }
+
+  @Override
+  public Set<Dimension.Identifier> getAvailableDimensions() {
+    return Set.of(Dimension.Identifier.OVERWORLD, // TODO: return the actual set of dimensions on disk.
+      Dimension.Identifier.THE_NETHER,
+      Dimension.Identifier.THE_END
+    );
+  }
+
+  @Override
+  public Optional<Dimension.Identifier> getDefaultDimension() {
+    return Optional.empty();
+  }
+
+  @Override
+  public Dimension loadDimension(Dimension.Identifier dimensionId) {
+    currentDimension = loadDimension(
+      this,
+      getInfo().path(),
+      dimensionId,
+      this.playerEntities.stream().filter(player -> player.dimension.equals(dimensionId)).collect(Collectors.toSet()),
+      this.spawnPos
+    );
+    currentDimension.reloadPlayerData();
+    return currentDimension;
+  }
+
+  @NotNull
+  private static Dimension loadDimension(JavaWorld world, Path worldDirectory, Dimension.Identifier dimensionId, Set<PlayerEntityData> playerEntities, @Nullable Vector3i spawnPos) {
+    Path dimensionDirectory = worldDirectory.resolve("dimensions").resolve(dimensionId.namespace()).resolve(dimensionId.name());
+    if (Files.exists(dimensionDirectory)) {
+      // 26.1-snapshot-6 or later
+      return new JavaDimension(world, dimensionId, dimensionDirectory, playerEntities, spawnPos);
+    }
+
+    dimensionDirectory = switch (dimensionId.getNamespacedName()) { // TODO in Java 21+ we can use `switch (dimensionId)` here
+      case "minecraft:the_nether" -> worldDirectory.resolve("DIM-1");
+      case "minecraft:the_end" -> worldDirectory.resolve("DIM1");
+      default -> worldDirectory;
+    };
+    if (Files.isDirectory(dimensionDirectory.resolve("region3d"))) {
+      return new CubicDimension(world, dimensionId, dimensionDirectory, playerEntities, spawnPos);
+    } else {
+      return new JavaDimension(world, dimensionId, dimensionDirectory, playerEntities, spawnPos);
+    }
+  }
+
+  public Optional<UUID> getSingleplayerPlayerUuid() {
+    return Optional.ofNullable(singleplayerPlayerUuid);
+  }
+
+  @NotNull
+  private static Set<PlayerEntityData> getPlayerEntityData(Path worldDirectory, Tag player) {
+    Set<PlayerEntityData> playerEntities = new HashSet<>();
+    if (!player.isError()) {
+      playerEntities.add(new PlayerEntityData(player));
+    }
+    loadAdditionalPlayers(worldDirectory, playerEntities);
+    return playerEntities;
+  }
+
+  private static void loadAdditionalPlayers(Path worldDirectory, Set<PlayerEntityData> playerEntities) {
+    loadPlayerData(worldDirectory.resolve("players"), playerEntities);
+    loadPlayerData(worldDirectory.resolve("playerdata"), playerEntities);
+    loadPlayerData(worldDirectory.resolve("players").resolve("data"), playerEntities); // 26.1-snapshot-6 or later
+  }
+
+  private static void loadPlayerData(Path playerDataDirectory, Set<PlayerEntityData> playerEntities) {
+    if (Files.isDirectory(playerDataDirectory)) {
+      try (DirectoryStream<Path> paths = Files.newDirectoryStream(playerDataDirectory)) {
+        for (Path player : paths) {
+          try (DataInputStream in = new DataInputStream(
+            new GZIPInputStream(new FileInputStream(player.toFile())))) {
+            playerEntities.add(new PlayerEntityData(NamedTag.read(in).unpack()));
+          } catch (IOException e) {
+            Log.infof("Could not read player data file '%s'", player.toAbsolutePath());
+          }
+        }
+      } catch (IOException e) {
+        Log.infof("Could not list player data directory '%s'", playerDataDirectory.toAbsolutePath());
+      }
+    }
+  }
+
+  /**
+   * Reload player data for the current dimension. This method is not in Dimension because players are per-world, not per-dimension
+   * @return {@code true} if player data was reloaded.
+   */
+  synchronized boolean reloadPlayerData() {
+    Path worldFile = getInfo().path().resolve("level.dat");
+    long lastModified;
+    try {
+      lastModified = Files.getLastModifiedTime(worldFile).toMillis();
+    } catch (IOException e) {
+      return false;
+    }
+    if (lastModified == playerDataTimestamp) {
+      return false;
+    }
+    Log.infof("world %s: timestamp updated: reading player data", getInfo().name());
+    playerDataTimestamp = lastModified;
+
+    try (FileInputStream fin = new FileInputStream(worldFile.toFile());
+         InputStream gzin = new GZIPInputStream(fin);
+         DataInputStream in = new DataInputStream(gzin)) {
+      Set<String> request = new HashSet<>();
+      request.add(".Data.Player");
+      request.add(".Data.singleplayer_uuid");
+      Map<String, Tag> result = NamedTag.quickParse(in, request);
+      Tag player = result.get(".Data.Player");
+      Tag singleplayerUuid = result.get(".Data.singleplayer_uuid");
+      if (singleplayerUuid.isIntArray(4)) {
+        singleplayerPlayerUuid = UuidUtil.intsToUuid(singleplayerUuid.intArray());
+      } else if (!player.isError()) {
+        singleplayerPlayerUuid = PlayerEntityData.getUuid(player);
+      }
+
+      this.playerEntities.clear();
+      this.playerEntities.addAll(getPlayerEntityData(getInfo().path(), player));
+    } catch (IOException e) {
+      Log.infof("Could not read the level.dat file for world %s while trying to reload player data!", getInfo().name());
+      return false;
+    }
+    return true;
+  }
+
+  private record WorldData(String levelName, long modTime, Map<String, Tag> tags) {}
+  private static <T> Optional<T> readWorldData(@NotNull Path worldDirectory, LoggedWarnings warnings, Function<WorldData, T> consumer) {
+    String levelName = worldDirectory.getFileName().toString();
+    Path levelDat = worldDirectory.resolve("level.dat");
+    try (FileInputStream fin = new FileInputStream(levelDat.toFile());
+         InputStream gzin = new GZIPInputStream(fin);
+         DataInputStream in = new DataInputStream(gzin)) {
+      long modtime = Files.getLastModifiedTime(levelDat).toMillis();
+      Set<String> request = new HashSet<>();
+      request.add(".Data.version");
+      request.add(".Data.Version.Id");
+      request.add(".Data.RandomSeed");
+      request.add(".Data.Player");
+      request.add(".Data.singleplayer_uuid");
+      request.add(".Data.LevelName");
+      request.add(".Data.GameType");
+
+      Map<String, Tag> result = NamedTag.quickParse(in, request);
+
+      Tag version = result.get(".Data.version");
+      if (warnings == LoggedWarnings.NORMAL && version.intValue() != NBT_VERSION) {
+        Log.warnf("The world format for the world %s is not supported by Chunky.\n" + "Will attempt to load the world anyway.",
+          levelName);
+      }
+
+      return Optional.of(consumer.apply(new WorldData(levelName, modtime, result)));
+    } catch (FileNotFoundException e) {
+      if (warnings == LoggedWarnings.NORMAL) {
+        Log.infof("Could not find level.dat file for world %s!", levelName);
+      }
+    } catch (IOException e) {
+      if (warnings == LoggedWarnings.NORMAL) {
+        Log.infof("Could not read the level.dat file for world %s!", levelName);
+      }
+    }
+    return Optional.empty();
+  }
+}
diff --git a/chunky/src/java/se/llbit/chunky/world/java/JavaWorldFormat.java b/chunky/src/java/se/llbit/chunky/world/java/JavaWorldFormat.java
new file mode 100644
index 0000000000..9de5a4fcf1
--- /dev/null
+++ b/chunky/src/java/se/llbit/chunky/world/java/JavaWorldFormat.java
@@ -0,0 +1,58 @@
+package se.llbit.chunky.world.java;
+
+import se.llbit.chunky.world.World;
+import se.llbit.chunky.world.worldformat.WorldFormat;
+import se.llbit.util.annotation.NotNull;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Optional;
+
+public class JavaWorldFormat implements WorldFormat {
+  public static final String NAME = "Java (Anvil)";
+  public static final String ID = "JAVA_ANVIL";
+
+  @Override
+  public String getName() {
+    return NAME;
+  }
+
+  @Override
+  public String getDescription() {
+    return "The Minecraft world format for Java worlds since 1.2.1 (12w07a)";
+  }
+
+  @Override
+  public String getId() {
+    return ID;
+  }
+
+  @Override
+  public boolean isValid(@NotNull Path path) {
+    if (Files.isDirectory(path)) {
+      Path levelDat = path.resolve("level.dat");
+      return Files.exists(levelDat) && Files.isRegularFile(levelDat);
+    }
+    return false;
+  }
+
+  @NotNull
+  @Override
+  public Optional<World.Info> getWorldInfo(@NotNull Path path) {
+    if (!Files.isDirectory(path)) {
+      return Optional.empty();
+    }
+    Path levelDat = path.resolve("level.dat");
+    if (!Files.exists(levelDat) || !Files.isRegularFile(levelDat)) {
+      return Optional.empty();
+    }
+
+    return JavaWorld.loadWorldInfo(path, World.LoggedWarnings.SILENT, this);
+  }
+
+  @NotNull
+  @Override
+  public World loadWorld(@NotNull World.Info info) {
+    return JavaWorld.loadWorld(info, World.LoggedWarnings.NORMAL);
+  }
+}
diff --git a/chunky/src/java/se/llbit/chunky/world/region/MCRegion.java b/chunky/src/java/se/llbit/chunky/world/java/region/JavaRegion.java
similarity index 95%
rename from chunky/src/java/se/llbit/chunky/world/region/MCRegion.java
rename to chunky/src/java/se/llbit/chunky/world/java/region/JavaRegion.java
index e6cee2dda4..606f8c539b 100644
--- a/chunky/src/java/se/llbit/chunky/world/region/MCRegion.java
+++ b/chunky/src/java/se/llbit/chunky/world/java/region/JavaRegion.java
@@ -14,7 +14,7 @@
  * You should have received a copy of the GNU General Public License
  * along with Chunky.  If not, see <http://www.gnu.org/licenses/>.
  */
-package se.llbit.chunky.world.region;
+package se.llbit.chunky.world.java.region;
 
 import java.io.*;
 import java.util.Iterator;
@@ -24,6 +24,10 @@
 import se.llbit.chunky.chunk.ChunkLoadingException;
 import se.llbit.chunky.plugin.PluginApi;
 import se.llbit.chunky.world.*;
+import se.llbit.chunky.world.java.JavaChunk;
+import se.llbit.chunky.world.java.JavaDimension;
+import se.llbit.chunky.world.region.ChunkReadException;
+import se.llbit.chunky.world.region.Region;
 import se.llbit.log.Log;
 import se.llbit.nbt.ErrorTag;
 import se.llbit.nbt.NamedTag;
@@ -42,19 +46,8 @@
  *
  * @author Jesper Öqvist <jesper@llbit.se>
  */
-public class MCRegion implements Region {
-
-  /**
-   * Region X chunk width
-   */
-  public static final int CHUNKS_X = 32;
-
-  /**
-   * Region Z chunk width
-   */
-  public static final int CHUNKS_Z = 32;
-
-  private static final int NUM_CHUNKS = CHUNKS_X * CHUNKS_Z;
+public class JavaRegion implements Region {
+  private static final int NUM_CHUNKS = Region.CHUNKS_X * Region.CHUNKS_Z;
 
   /**
    * Sector size in bytes.
@@ -63,7 +56,7 @@ public class MCRegion implements Region {
 
   private final Chunk[] chunks = new Chunk[NUM_CHUNKS];
   private final RegionPosition position;
-  private final Dimension dimension;
+  private final JavaDimension dimension;
   private final String fileName;
   private long regionFileTime = 0;
   private final int[] chunkTimestamps = new int[NUM_CHUNKS];
@@ -80,12 +73,12 @@ private static int getMCAChunkIndex(ChunkPosition chunkPos) {
    *
    * @param pos the region position
    */
-  public MCRegion(RegionPosition pos, Dimension dimension) {
+  public JavaRegion(RegionPosition pos, JavaDimension dimension) {
     this.dimension = dimension;
     fileName = pos.getMcaName();
     position = pos;
-    for (int z = 0; z < CHUNKS_Z; ++z) {
-      for (int x = 0; x < CHUNKS_X; ++x) {
+    for (int z = 0; z < Region.CHUNKS_Z; ++z) {
+      for (int x = 0; x < Region.CHUNKS_X; ++x) {
         chunks[getMCAChunkIndex(x, z)] = EmptyChunk.INSTANCE;
       }
     }
@@ -156,7 +149,7 @@ public synchronized void parse(int minY, int maxY) {
           int loc = file.readInt();
           if (loc != 0) {
             if (chunk.isEmpty()) {
-              chunk = new Chunk(pos, dimension);
+              chunk = new JavaChunk(pos, dimension);
               setChunk(pos, chunk);
             }
           } else {
diff --git a/chunky/src/java/se/llbit/chunky/world/region/MCRegionChangeWatcher.java b/chunky/src/java/se/llbit/chunky/world/java/region/JavaRegionChangeWatcher.java
similarity index 75%
rename from chunky/src/java/se/llbit/chunky/world/region/MCRegionChangeWatcher.java
rename to chunky/src/java/se/llbit/chunky/world/java/region/JavaRegionChangeWatcher.java
index b3e9e3bcc0..887f9c1b1b 100644
--- a/chunky/src/java/se/llbit/chunky/world/region/MCRegionChangeWatcher.java
+++ b/chunky/src/java/se/llbit/chunky/world/java/region/JavaRegionChangeWatcher.java
@@ -14,24 +14,26 @@
  * You should have received a copy of the GNU General Public License
  * along with Chunky.  If not, see <http://www.gnu.org/licenses/>.
  */
-package se.llbit.chunky.world.region;
+package se.llbit.chunky.world.java.region;
 
 import javafx.application.Platform;
 import se.llbit.chunky.PersistentSettings;
 import se.llbit.chunky.map.MapView;
 import se.llbit.chunky.map.WorldMapLoader;
-import se.llbit.chunky.world.ChunkPosition;
 import se.llbit.chunky.world.ChunkView;
-import se.llbit.chunky.world.Dimension;
+import se.llbit.chunky.world.HeightRange;
 import se.llbit.chunky.world.RegionPosition;
+import se.llbit.chunky.world.java.JavaDimension;
+import se.llbit.chunky.world.region.Region;
+import se.llbit.chunky.world.region.RegionChangeWatcher;
 
 /**
  * Monitors filesystem for changes to region files.
  *
  * @author Jesper Öqvist <jesper@llbit.se>
  */
-public class MCRegionChangeWatcher extends RegionChangeWatcher {
-  public MCRegionChangeWatcher(WorldMapLoader loader, MapView mapView) {
+public class JavaRegionChangeWatcher extends RegionChangeWatcher {
+  public JavaRegionChangeWatcher(WorldMapLoader loader, MapView mapView) {
     super(loader, mapView, "Region Refresher");
   }
 
@@ -39,7 +41,8 @@ public MCRegionChangeWatcher(WorldMapLoader loader, MapView mapView) {
     try {
       while (!isInterrupted()) {
         sleep(3000);
-        Dimension dimension = mapLoader.getWorld().currentDimension();
+        // RegionChangeWatcher is only created by JavaDimension, so this cast is always safe.
+        JavaDimension dimension = (JavaDimension) mapLoader.getWorld().currentDimension();
         if (dimension.reloadPlayerData()) {
           if (PersistentSettings.getFollowPlayer()) {
             Platform.runLater(() -> dimension.getPlayerPos().ifPresent(mapView::panTo));
@@ -49,9 +52,10 @@ public MCRegionChangeWatcher(WorldMapLoader loader, MapView mapView) {
         for (int rx = theView.prx0; rx <= theView.prx1; ++rx) {
           for (int rz = theView.prz0; rz <= theView.prz1; ++rz) {
             RegionPosition pos = new RegionPosition(rx, rz);
-            Region region = dimension.getRegionWithinRange(pos, theView.yMin, theView.yMax);
+            HeightRange heightRange = new HeightRange(theView.yMin, theView.yMax);
+            Region region = dimension.getRegionWithinRange(pos, heightRange);
             if (region.isEmpty()) {
-              if (dimension.regionExistsWithinRange(pos, theView.yMin, theView.yMax)) {
+              if (dimension.hasRegionWithinRange(pos, heightRange)) {
                 region = dimension.createRegion(pos);
               }
               dimension.setRegion(pos, region);
diff --git a/chunky/src/java/se/llbit/chunky/world/listeners/ChunkUpdateListener.java b/chunky/src/java/se/llbit/chunky/world/listeners/ChunkUpdateListener.java
index 436abd9507..84084a277c 100644
--- a/chunky/src/java/se/llbit/chunky/world/listeners/ChunkUpdateListener.java
+++ b/chunky/src/java/se/llbit/chunky/world/listeners/ChunkUpdateListener.java
@@ -18,7 +18,7 @@
 
 import se.llbit.chunky.world.ChunkPosition;
 import se.llbit.chunky.world.RegionPosition;
-import se.llbit.chunky.world.region.MCRegion;
+import se.llbit.chunky.world.region.Region;
 
 import java.util.Collection;
 
@@ -33,8 +33,8 @@ default void chunkUpdated(ChunkPosition chunkPosition) {}
   default void regionChunksUpdated(RegionPosition region) {
     int minChunkX = region.x << 5;
     int minChunkZ = region.z << 5;
-    for (int chunkX = minChunkX; chunkX < minChunkX + MCRegion.CHUNKS_X; chunkX++) {
-      for (int chunkZ = minChunkZ; chunkZ < minChunkZ + MCRegion.CHUNKS_Z; chunkZ++) {
+    for (int chunkX = minChunkX; chunkX < minChunkX + Region.CHUNKS_X; chunkX++) {
+      for (int chunkZ = minChunkZ; chunkZ < minChunkZ + Region.CHUNKS_Z; chunkZ++) {
         this.chunkUpdated(new ChunkPosition(chunkX, chunkZ));
       }
     }
diff --git a/chunky/src/java/se/llbit/chunky/world/region/Region.java b/chunky/src/java/se/llbit/chunky/world/region/Region.java
index f12662ef1e..3cd29239d3 100644
--- a/chunky/src/java/se/llbit/chunky/world/region/Region.java
+++ b/chunky/src/java/se/llbit/chunky/world/region/Region.java
@@ -6,6 +6,15 @@
 import se.llbit.chunky.world.RegionPosition;
 
 public interface Region extends Iterable<Chunk> {
+  /**
+   * Region X chunk width
+   */
+  int CHUNKS_X = 32;
+  /**
+   * Region Z chunk width
+   */
+  int CHUNKS_Z = 32;
+
   /**
    * @return Chunk at (x, z)
    */
diff --git a/chunky/src/java/se/llbit/chunky/world/region/RegionParser.java b/chunky/src/java/se/llbit/chunky/world/region/RegionParser.java
index b25f0771c0..e47c641179 100644
--- a/chunky/src/java/se/llbit/chunky/world/region/RegionParser.java
+++ b/chunky/src/java/se/llbit/chunky/world/region/RegionParser.java
@@ -61,7 +61,7 @@ public RegionParser(WorldMapLoader loader, RegionQueue queue, MapView mapView) {
         ChunkView map = mapView.getMapView();
         if (map.isRegionVisible(position)) {
           Dimension dimension = mapLoader.getWorld().currentDimension();
-          Region region = dimension.getRegionWithinRange(position, mapView.getYMin(), mapView.getYMax());
+          Region region = dimension.getRegionWithinRange(position, new HeightRange(mapView.getYMin(), mapView.getYMax()));
           region.parse(mapView.getYMin(), mapView.getYMax());
           Mutable<ChunkData> chunkData = new Mutable<>(null);
           for (Chunk chunk : region) {
diff --git a/chunky/src/java/se/llbit/chunky/world/worldformat/WorldFormat.java b/chunky/src/java/se/llbit/chunky/world/worldformat/WorldFormat.java
new file mode 100644
index 0000000000..3a4448fbff
--- /dev/null
+++ b/chunky/src/java/se/llbit/chunky/world/worldformat/WorldFormat.java
@@ -0,0 +1,51 @@
+package se.llbit.chunky.world.worldformat;
+
+import se.llbit.chunky.world.World;
+import se.llbit.util.Registerable;
+import se.llbit.util.annotation.NotNull;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.Optional;
+
+/**
+ * A {@link WorldFormat} determines whether paths on disk are valid for its world type, and can then load that
+ * {@link World} into chunky.
+ *
+ * <p>Implementations should be <b><u>stateless</u></b>, and never cache world validity.</p>
+ *
+ * <p>Implementations will be queried for many different paths via {@link #isValid(Path)}.
+ * The same {@link Path} is likely to be checked more than once over the lifetime of the {@link WorldFormat}</p>
+ */
+public interface WorldFormat extends Registerable {
+  /**
+   * Determine whether a {@link Path} is valid for this {@link WorldFormat}
+   *
+   * <p>This method will be called on every possible world directory
+   * (typically this is every directory in `.minecraft/saves`).</p>
+   *
+   * @param path The path to the world.
+   * @return Whether this is a valid world under this world format.
+   */
+  boolean isValid(@NotNull Path path);
+
+  /**
+   * Load metadata about a world
+   *
+   * <p>Calls to this method do not indicate that any blocks will be loaded from the world. As such implementations
+   * should do <b><u>minimal</u></b> work to load the metadata for a world.</p>
+   *
+   * @param path The path to the world
+   * @return The {@link World.Info}, if it was created successfully.
+   */
+  @NotNull Optional<World.Info> getWorldInfo(@NotNull Path path);
+
+  /**
+   * Load the world represented by the given world info.
+   *
+   * @param info The world info.
+   * @return The loaded world, or an empty world if the world was not loadable.
+   * @throws IOException When something goes wrong when loading the world. Will be reported to the user.
+   */
+  @NotNull World loadWorld(@NotNull World.Info info) throws IOException;
+}
\ No newline at end of file
diff --git a/chunky/src/java/se/llbit/chunky/world/worldformat/WorldFormats.java b/chunky/src/java/se/llbit/chunky/world/worldformat/WorldFormats.java
new file mode 100644
index 0000000000..3df89315d6
--- /dev/null
+++ b/chunky/src/java/se/llbit/chunky/world/worldformat/WorldFormats.java
@@ -0,0 +1,56 @@
+package se.llbit.chunky.world.worldformat;
+
+import se.llbit.chunky.world.EmptyWorld;
+import se.llbit.chunky.world.World;
+import se.llbit.chunky.world.java.JavaWorldFormat;
+import se.llbit.log.Log;
+import se.llbit.util.annotation.NotNull;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class WorldFormats {
+  /**
+   * Uses an ordered hashmap to guarantee a consistent encounter order (and that {@link JavaWorldFormat} is checked first)
+   */
+  private static final LinkedHashMap<String, WorldFormat> worldFormatsById = new LinkedHashMap<>();
+
+  public static void addWorldFormat(WorldFormat worldFormat) {
+    worldFormatsById.put(worldFormat.getId(), worldFormat);
+  }
+
+  public static Map<String, WorldFormat> getWorldFormats() {
+    return Collections.unmodifiableMap(worldFormatsById);
+  }
+
+  public static Optional<WorldFormat> getWorldFormat(String id) {
+    return Optional.ofNullable(worldFormatsById.get(id));
+  }
+
+  static {
+    addWorldFormat(new JavaWorldFormat());
+  }
+
+  @NotNull
+  public static Collection<World.Info> getInfos(Path path) {
+    return getWorldFormats().values().stream()
+      .filter(format -> format.isValid(path))
+      .map(format -> format.getWorldInfo(path))
+      .flatMap(Optional::stream)
+      .collect(Collectors.toList());
+  }
+
+  @NotNull
+  public static World createWorld(@NotNull World.Info info) {
+    try {
+      return info.worldFormat().loadWorld(info);
+    } catch (IOException e) {
+      Log.error(String.format("An error occurred when trying to load a world using format `%s` from %s",
+        info.worldFormat().getName(), info.path().toAbsolutePath()), e
+      );
+    }
+    return EmptyWorld.INSTANCE;
+  }
+}
diff --git a/lib/src/se/llbit/chunky/PersistentSettings.java b/lib/src/se/llbit/chunky/PersistentSettings.java
index b5758e0035..9f7e371285 100644
--- a/lib/src/se/llbit/chunky/PersistentSettings.java
+++ b/lib/src/se/llbit/chunky/PersistentSettings.java
@@ -190,6 +190,16 @@ public static File getLastWorld() {
     return lastWorld.isEmpty() ? null : new File(lastWorld);
   }
 
+  public static void setLastWorldFormat(String worldFormat) {
+    settings.setString("lastWorldFormat", worldFormat);
+    save();
+  }
+
+  /** @return the world format of the previously loaded world. */
+  public static String getLastWorldFormat() {
+    return settings.getString("lastWorldFormat", "");
+  }
+
   public static void setSkinDirectory(File directory) {
     settings.setString("skinDirectory", directory.getAbsolutePath());
     save();