diff --git a/src/activities/overworld/worldgen.rs b/src/activities/overworld/worldgen.rs
index 2a84e41..73dfd21 100644
--- a/src/activities/overworld/worldgen.rs
+++ b/src/activities/overworld/worldgen.rs
@@ -1,9 +1,90 @@
+use comfy::{IVec2, UVec2};
+use std::collections::HashMap;
+
+enum MovementCost {
+	/// No movement possible - cost infinitely high.
+	Infinite,
+	/// There is a path for this movement - movement is cheap.
+	Path,
+	/// There is no path and no obstacle.
+	Default,
+	/// There is an obstacle (i.e. fence) - movement is expensive.
+	Obstacle
+}
 
 #[derive(Debug)]
-pub struct Overworld;
+struct Tile;
 
-impl Default for Overworld {
-	fn default() -> Self {
-		Self
+impl Tile {
+	pub fn can_stand_inside(&self) -> bool {
+		unimplemented!()
+	}
+	pub fn movement_cost_left(&self) -> MovementCost {
+		unimplemented!()
+	}
+	pub fn movement_cost_right(&self) -> MovementCost {
+		unimplemented!()
+	}
+	pub fn movement_cost_up(&self) -> MovementCost {
+		unimplemented!()
+	}
+	pub fn movement_cost_down(&self) -> MovementCost {
+		unimplemented!()
+	}
+	pub fn can_enter_house(&self) -> bool {
+		unimplemented!()
+	}
+}
+
+/// The size of a chunk (both width and height). This value squared gives the amount of
+/// tiles in the chunk.
+const CHUNK_SIZE: u32 = 100;
+
+/// Chunks
+#[derive(Debug)]
+pub struct Chunk {
+	/// All tiles within this chunk.
+	tiles: [Tile; (CHUNK_SIZE * CHUNK_SIZE) as usize],
+	/// All paths that leave this chunk on the left hand side.
+	paths_left: Vec<u32>,
+	/// All paths that leave this chunk on the right hand side.
+	paths_right: Vec<u32>,
+	/// All paths that leave this chunk on the bottom side.
+	paths_bottom: Vec<u32>,
+	/// All paths that leave this chunk on the top side.
+	paths_top: Vec<u32>
+}
+
+impl Chunk {
+	fn get_tile(&self, local_chunk_coords: UVec2) -> Option<&Tile> {
+		self.tiles
+			.get((local_chunk_coords.y * CHUNK_SIZE + local_chunk_coords.x) as usize)
+	}
+}
+
+#[derive(Debug, Default)]
+pub struct Overworld {
+	chunks: HashMap<IVec2, Chunk>
+}
+
+impl Overworld {
+	/// Return a [`Tile`] at the given world coordinates, or `None` if that tile has not
+	/// been generated yet.
+	fn get_tile(&self, world_coords: IVec2) -> Option<&Tile> {
+		let tile_coords = IVec2 {
+			x: world_coords.x.div_euclid(CHUNK_SIZE as _),
+			y: world_coords.y.div_euclid(CHUNK_SIZE as _)
+		};
+		let local_coords = UVec2 {
+			x: world_coords.x.rem_euclid(CHUNK_SIZE as _) as _,
+			y: world_coords.y.rem_euclid(CHUNK_SIZE as _) as _
+		};
+
+		let chunk = self.chunks.get(&tile_coords)?;
+		chunk.get_tile(local_coords)
+	}
+
+	fn get_or_generate_tile(&self, world_coords: IVec2) -> &Tile {
+		unimplemented!()
 	}
 }
diff --git a/src/main.rs b/src/main.rs
index a310d1e..aa9f605 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,7 +9,7 @@ const GAME_NAME: &str = "Powercreep";
 #[derive(Debug, Default)]
 struct State {
 	activity: Activity,
-	overworld: Overworld,
+	overworld: Overworld
 }
 
 impl GameLoop for State {