diff --git a/source/Game.cpp b/source/Game.cpp
index 446972e..33783e6 100644
--- a/source/Game.cpp
+++ b/source/Game.cpp
@@ -49,11 +49,12 @@ Game::generate() {
 	for (int x = 1; x < 5; x++)
 		mTileManager.setTile(TileManager::TilePosition(x, 4), TileManager::Type::WALL);
 
-	mCollection.insert(std::shared_ptr<Sprite>(new Enemy(mWorld, mCollection, mPathfinder,
+	mWorld.insert(std::shared_ptr<Sprite>(new Enemy(mWorld, mPathfinder,
 			Vector2f(400.0f, 200.0f), Yaml("enemy.yaml"))));
 
-	mPlayer = std::unique_ptr<Player>(new Player(mWorld, mCollection, mPathfinder,
+	mPlayer = std::shared_ptr<Player>(new Player(mWorld, mPathfinder,
 			Vector2f(200.0f, 100.0f), Yaml("player.yaml")));
+	mWorld.insert(mPlayer);
 }
 /**
  * Closes window.
@@ -77,9 +78,9 @@ Game::loop() {
 		}
 
 		Character::think(elapsed);
-		mCollection.checkDelete();
+		mWorld.checkDelete();
 
-		mWorld.step();
+		mWorld.step(elapsed);
 
 		render();
 	}
@@ -203,9 +204,7 @@ Game::render() {
 	// Render world and dynamic stuff.
 	mWindow.setView(mView);
 
-	mWindow.draw(mTileManager);
-	mWindow.draw(mCollection);
-	mWindow.draw(*mPlayer);
+	mWindow.draw(mWorld);
 
 	// Render GUI and static stuff.
 	mWindow.setView(mWindow.getDefaultView());
diff --git a/source/Game.h b/source/Game.h
index 5f3d50a..c8fd530 100644
--- a/source/Game.h
+++ b/source/Game.h
@@ -13,16 +13,14 @@
 
 #include <Thor/Resources.hpp>
 
-#include "World.h"
 #include "sprites/TileManager.h"
 #include "sprites/Player.h"
 #include "types/String.h"
-#include "util/Collection.h"
+#include "World.h"
 #include "util/Pathfinder.h"
 
-class World;
 class Player;
-class Collection;
+class World;
 
 /*
  * Use vertex for tiles.
@@ -51,16 +49,14 @@ private:
 private:
 	static const int FPS_GOAL;
 
-	World mWorld;
-
 	sf::RenderWindow& mWindow;
 	sf::Clock mClock;
 	sf::View mView;
 
-	Collection mCollection;
+	World mWorld;
 	TileManager mTileManager;
 	Pathfinder mPathfinder;
-	std::unique_ptr<Player> mPlayer;
+	std::shared_ptr<Player> mPlayer;
 
 	bool mQuit;
 	bool mPaused;
diff --git a/source/World.cpp b/source/World.cpp
old mode 100644
new mode 100755
index bafd7e5..a6d0c24
--- a/source/World.cpp
+++ b/source/World.cpp
@@ -1,23 +1,70 @@
-/*
- * World.cpp
- *
- *  Created on: 22.12.2012
- *      Author: Felix
- */
-
-#include "World.h"
-
-World::World() {
-	// TODO Auto-generated constructor stub
-
-}
-
-World::~World() {
-	// TODO Auto-generated destructor stub
-}
-
-
-void
-World::step() {
-
-}
+/*
+ * World.cpp
+ *
+ *  Created on: 29.08.2012
+ *      Author: Felix
+ */
+
+#include "World.h"
+
+#include <algorithm>
+
+/**
+ * Insert a drawable into the group. Drawables should only be handled with shared_ptr.
+ * An object can't be inserted more than once at the same level.
+ */
+void
+World::insert(std::shared_ptr<Sprite> drawable) {
+	Body::Category cat = drawable->getCategory();
+	auto item = std::find(mDrawables[cat].begin(), mDrawables[cat].end(), drawable);
+	if (item == mDrawables[cat].end()) {
+		mDrawables[cat].push_back(drawable);
+	}
+}
+
+/**
+ * Removes a drawable from the group.
+ */
+void
+World::remove(std::shared_ptr<Sprite> drawable) {
+	for (auto v = mDrawables.begin(); v != mDrawables.end(); v++) {
+		auto item = std::find(v->second.begin(), v->second.end(), drawable);
+		if (item != v->second.end()) {
+			   v->second.erase(item);
+		}
+	}
+}
+
+void
+World::step(int elapsed) {
+}
+
+/**
+ * Deletes any sprites which return true for getDelete().
+ */
+void
+World::checkDelete() {
+	for (auto v = mDrawables.begin(); v != mDrawables.end(); v++) {
+		for (auto item = v->second.begin(); item != v->second.end(); ) {
+			if ((*item)->getDelete()) {
+				item = v->second.erase(item);
+			}
+			else {
+				item++;
+			}
+		}
+	}
+}
+
+/**
+ * Draws all elements in the group.
+ */
+void
+World::draw(sf::RenderTarget& target, sf::RenderStates states) const {
+	for (auto v = mDrawables.begin(); v != mDrawables.end(); v++) {
+		for (auto item : v->second) {
+			target.draw(static_cast<sf::Drawable&>(*item), states);
+		}
+	}
+}
+
diff --git a/source/World.h b/source/World.h
old mode 100644
new mode 100755
index 166aeed..311449f
--- a/source/World.h
+++ b/source/World.h
@@ -1,19 +1,45 @@
-/*
- * World.h
- *
- *  Created on: 22.12.2012
- *      Author: Felix
- */
-
-#ifndef DG_WORLD_H_
-#define DG_WORLD_H_
-
-class World {
-public:
-	World();
-	~World();
-
-	void step();
-};
-
-#endif /* DG_WORLD_H_ */
+/*
+ * World.h
+ *
+ *  Created on: 29.08.2012
+ *      Author: Felix
+ */
+
+#ifndef DG_WORLD_H_
+#define DG_WORLD_H_
+
+#include <map>
+#include <vector>
+
+#include <SFML/Graphics.hpp>
+
+#include "abstract/Body.h"
+#include "abstract/Sprite.h"
+
+class Body;
+class Sprite;
+
+/**
+ * A collection of sprites, which can be put into different layers.
+ *
+ * Uses Sprite instead of sf::Drawable to also manage deleting objects.
+ * Render order is determined by Physical::Category (higher number on top).
+ */
+class World : public sf::Drawable {
+// Public functions.
+public:
+	void insert(std::shared_ptr<Sprite> drawable);
+	void remove(std::shared_ptr<Sprite> drawable);
+	void step(int elapsed);
+	void checkDelete();
+
+// Private functions.
+private:
+    void draw(sf::RenderTarget& target, sf::RenderStates states) const;
+
+// Private variables.
+private:
+	std::map<Body::Category, std::vector<std::shared_ptr<Sprite> > > mDrawables;
+};
+
+#endif /* DG_WORLD_H_ */
diff --git a/source/abstract/Body.cpp b/source/abstract/Body.cpp
index 77a25e2..8be5c53 100755
--- a/source/abstract/Body.cpp
+++ b/source/abstract/Body.cpp
@@ -37,9 +37,8 @@ Body::~Body() {
 /**
  * Initializes container.
  */
-Body::Data::Data(World& world, const Vector2f& position, float angle,
+Body::Data::Data(const Vector2f& position, float angle,
 		Category category, unsigned short maskExclude) :
-		world(world),
 		position(position),
 		angle(angle),
 		category(category),
diff --git a/source/abstract/Body.h b/source/abstract/Body.h
index 6160217..00b69c6 100755
--- a/source/abstract/Body.h
+++ b/source/abstract/Body.h
@@ -8,12 +8,10 @@
 #ifndef DG_BODY_H_
 #define DG_BODY_H_
 
-#include "../World.h"
 #include "../types/String.h"
 #include "../types/Vector.h"
 #include "../util/Yaml.h"
 
-class World;
 class Yaml;
 
 /**
@@ -44,9 +42,7 @@ public:
 	class Data {
 	public:
 		Data() = default;
-		Data(World& world, const Vector2f& position, float angle,
-				Category category, unsigned short maskExclude);
-		World& world;
+		Data(const Vector2f& position, float angle,	Category category, unsigned short maskExclude);
 		const Vector2f& position;
 		float angle;
 		Category category;
diff --git a/source/abstract/Character.cpp b/source/abstract/Character.cpp
index f8f3aa9..ca1f3bf 100644
--- a/source/abstract/Character.cpp
+++ b/source/abstract/Character.cpp
@@ -25,16 +25,15 @@ std::vector<Character*> Character::mCharacterInstances = std::vector<Character*>
 /**
  * Saves pointer to this instance in static var for think().
  */
-Character::Character(World& world, Collection& collection, Pathfinder& pathfinder,
+Character::Character(World& world, Pathfinder& pathfinder,
 		const Data& data, const Yaml& config) :
 		Sprite(config, data),
-		mCollection(collection),
-		mPathfinder(pathfinder),
 		mWorld(world),
+		mPathfinder(pathfinder),
 		mMaxHealth(config.get(KEY_HEALTH, DEFAULT_HEALTH)),
 		mCurrentHealth(mMaxHealth),
 		mMovementSpeed(config.get(KEY_SPEED, DEFAULT_SPEED)),
-		mWeapon(world, collection, *this, Yaml("weapon.yaml")),
+		mWeapon(world, *this, Yaml("weapon.yaml")),
 		mStartPathfinding(false) {
 		mCharacterInstances.push_back(this);
 }
@@ -47,8 +46,7 @@ Character::~Character() {
 	assert(it != mCharacterInstances.end());
 	mCharacterInstances.erase(it);
 
-	mCollection.insert(std::shared_ptr<Sprite>(new Corpse(mWorld,
-			getPosition(), Yaml("body.yaml"))));
+	mWorld.insert(std::shared_ptr<Sprite>(new Corpse(getPosition(), Yaml("body.yaml"))));
 }
 
 /**
diff --git a/source/abstract/Character.h b/source/abstract/Character.h
index 12ece5f..0c08b69 100644
--- a/source/abstract/Character.h
+++ b/source/abstract/Character.h
@@ -30,7 +30,7 @@ class Yaml;
 class Character : public Sprite {
 // Public functions.
 public:
-	Character(World& world, Collection& collection, Pathfinder& pathfinder,
+	Character(World& world, Pathfinder& pathfinder,
 			const Data& data, const Yaml& config);
 	virtual ~Character() = 0;
 
@@ -58,9 +58,8 @@ private:
 
 	static std::vector<Character*> mCharacterInstances;
 
-	Collection& mCollection;
-	Pathfinder& mPathfinder;
 	World& mWorld;
+	Pathfinder& mPathfinder;
 
 	const int mMaxHealth;
 	int mCurrentHealth; //< Current health. Between 0 and mMaxHealth.
diff --git a/source/effects/Bullet.cpp b/source/effects/Bullet.cpp
index 39c6903..8d8ba8f 100755
--- a/source/effects/Bullet.cpp
+++ b/source/effects/Bullet.cpp
@@ -25,9 +25,9 @@ const float Bullet::DEFAULT_SPEED = 500;
  * @param world Box2d world.
  * @param texture Texture to display for bullet.
  */
-Bullet::Bullet(const Vector2f& position, World& world, Body& shooter, float direction,
+Bullet::Bullet(const Vector2f& position, Body& shooter, float direction,
 	const Yaml& config) :
-		Particle(config, Data(world, position, 0, CATEGORY_PARTICLE, CATEGORY_PARTICLE)),
+		Particle(config, Data(position, 0, CATEGORY_PARTICLE, CATEGORY_PARTICLE)),
 		mShooter(shooter),
 		mDamage(config.get(KEY_DAMAGE, DEFAULT_DAMAGE)),
 		mSpeed(config.get(KEY_SPEED, DEFAULT_SPEED)) {
diff --git a/source/effects/Bullet.h b/source/effects/Bullet.h
index cd2481b..5bf1c2f 100755
--- a/source/effects/Bullet.h
+++ b/source/effects/Bullet.h
@@ -21,7 +21,7 @@ class Yaml;
 class Bullet : public Particle {
 // Public functions.
 public:
-	Bullet(const Vector2f& position, World& world, Body& shooter, float direction,
+	Bullet(const Vector2f& position, Body& shooter, float direction,
 			const Yaml& config);
 
 	void onCollide(Body& other, Category category);
diff --git a/source/items/Weapon.cpp b/source/items/Weapon.cpp
index 79e563d..88affdd 100755
--- a/source/items/Weapon.cpp
+++ b/source/items/Weapon.cpp
@@ -11,7 +11,7 @@
 
 #include <thor/Vectors.hpp>
 
-#include "../util/Collection.h"
+#include "../World.h"
 #include "../effects/Bullet.h"
 
 const String Weapon::KEY_BULLET = "bullet";
@@ -19,10 +19,10 @@ const String Weapon::DEFAULT_BULLET = "bullet.yaml";
 const String Weapon::KEY_INTERVAL = "interval";
 const int Weapon::DEFAULT_INTERVAL = 250;
 
-Weapon::Weapon(World& world, Collection& collection, Body& holder, const Yaml& config) :
-		Emitter(collection),
-		mHolder(holder),
+Weapon::Weapon(World& world, Body& holder, const Yaml& config) :
+		Emitter(world),
 		mWorld(world),
+		mHolder(holder),
 		mBullet(config.get(KEY_BULLET, DEFAULT_BULLET)),
 		mTimer(sf::milliseconds(config.get(KEY_INTERVAL, DEFAULT_INTERVAL))) {
 	Vector2i holderSize = mHolder.getSize();
@@ -50,6 +50,6 @@ Weapon::createParticle() {
 	// Minus to account for positive y-axis going downwards in SFML.
 	Vector2f offset(- mOffset);
 	thor::rotate(offset, mHolder.getAngle());
-	return std::shared_ptr<Particle>(new Bullet(mHolder.getPosition() + offset, mWorld,
+	return std::shared_ptr<Particle>(new Bullet(mHolder.getPosition() + offset,
 			mHolder, mHolder.getAngle(), Yaml(mBullet)));
 }
diff --git a/source/items/Weapon.h b/source/items/Weapon.h
index 12a84cf..4021ae6 100755
--- a/source/items/Weapon.h
+++ b/source/items/Weapon.h
@@ -29,7 +29,7 @@ class Yaml;
 class Weapon : public Emitter {
 // Public functions.
 public:
-	Weapon(World& world, Collection& collection, Body& holder, const Yaml& config);
+	Weapon(World& world, Body& holder, const Yaml& config);
 
 	void fire();
 
@@ -44,8 +44,8 @@ private:
 	static const String KEY_INTERVAL;
 	static const int DEFAULT_INTERVAL;
 
-	Body& mHolder;
 	World& mWorld;
+	Body& mHolder;
 
 	Vector2f mOffset; //< Offset to the point where bullets are inserted (from holder center).
 	const String mBullet;
diff --git a/source/particle/Emitter.cpp b/source/particle/Emitter.cpp
index 5901f60..6118a8a 100755
--- a/source/particle/Emitter.cpp
+++ b/source/particle/Emitter.cpp
@@ -7,7 +7,7 @@
 
 #include "Emitter.h"
 
-Emitter::Emitter(Collection& collection) :
+Emitter::Emitter(World& collection) :
 		mCollection(collection) {
 }
 
diff --git a/source/particle/Emitter.h b/source/particle/Emitter.h
index 1e5f214..6107ca7 100755
--- a/source/particle/Emitter.h
+++ b/source/particle/Emitter.h
@@ -9,17 +9,17 @@
 #define DG_EMITTER_H_
 
 #include "../abstract/Body.h"
-#include "../util/Collection.h"
+#include "../World.h"
 #include "Particle.h"
 
 class Body;
-class Collection;
+class World;
 class Particle;
 
 class Emitter {
 // Public functions.
 public:
-	Emitter(Collection& collection);
+	Emitter(World& collection);
 	virtual ~Emitter();
 
 // Protected functions.
@@ -30,7 +30,7 @@ protected:
 
 // Private variables.
 private:
-	Collection& mCollection;
+	World& mCollection;
 };
 
 #endif /* DG_EMITTER_H_ */
diff --git a/source/sprites/Corpse.cpp b/source/sprites/Corpse.cpp
index 4b3eb2e..05ea2f8 100644
--- a/source/sprites/Corpse.cpp
+++ b/source/sprites/Corpse.cpp
@@ -7,7 +7,7 @@
 
 #include "Corpse.h"
 
-Corpse::Corpse(World& world, const Vector2f& position, const Yaml& config) :
-		Sprite(config, Data(world, position, 0, CATEGORY_NONSOLID, MASK_NONE)) {
+Corpse::Corpse(const Vector2f& position, const Yaml& config) :
+		Sprite(config, Data(position, 0, CATEGORY_NONSOLID, MASK_NONE)) {
 }
 
diff --git a/source/sprites/Corpse.h b/source/sprites/Corpse.h
index 6e7bc80..b453301 100644
--- a/source/sprites/Corpse.h
+++ b/source/sprites/Corpse.h
@@ -17,7 +17,7 @@ class Yaml;
 class Corpse : public Sprite {
 // Public functions.
 public:
-	Corpse(World& world, const Vector2f& position, const Yaml& config);
+	Corpse(const Vector2f& position, const Yaml& config);
 };
 
 #endif /* DG_CORPSE_H_ */
diff --git a/source/sprites/Enemy.cpp b/source/sprites/Enemy.cpp
index 2271f60..282771f 100644
--- a/source/sprites/Enemy.cpp
+++ b/source/sprites/Enemy.cpp
@@ -9,13 +9,11 @@
 
 #include "Corpse.h"
 
-Enemy::Enemy(World& world, Collection& collection, Pathfinder& pathfinder,
+Enemy::Enemy(World& collection, Pathfinder& pathfinder,
 	const Vector2f& position, const Yaml& config) :
-		Character(world, collection, pathfinder,
-				Data(world, position, 0, CATEGORY_ACTOR, MASK_ALL),
-				config),
-		mWorld(world),
-		mCollection(collection) {
+		Character(collection, pathfinder,
+				Data(position, 0, CATEGORY_ACTOR, MASK_ALL),
+				config) {
 }
 
 void
diff --git a/source/sprites/Enemy.h b/source/sprites/Enemy.h
index 1c568d5..acf5ac2 100644
--- a/source/sprites/Enemy.h
+++ b/source/sprites/Enemy.h
@@ -8,32 +8,25 @@
 #ifndef DG_ENEMY_H_
 #define DG_ENEMY_H
 
-#include "../World.h"
 #include "../abstract/Character.h"
-#include "../util/Collection.h"
+#include "../World.h"
 #include "../types/Vector.h"
 #include "../util/Yaml.h"
 
-class World;
 class Character;
-class Collection;
+class World;
 class Instances;
 class Yaml;
 
 class Enemy : public Character {
 // Public functions.
 public:
-	Enemy(World& world, Collection& collection, Pathfinder& pathfinder,
+	Enemy(World& collection, Pathfinder& pathfinder,
 			const Vector2f& position, const Yaml& config);
 
 // Private functions.
 private:
 	void onThink(float elapsedTime);
-
-// Private variablese.
-private:
-	World& mWorld;
-	Collection& mCollection;
 };
 
 #endif /* DG_ENEMY_H_ */
diff --git a/source/sprites/Player.cpp b/source/sprites/Player.cpp
index f70a2fb..8703020 100644
--- a/source/sprites/Player.cpp
+++ b/source/sprites/Player.cpp
@@ -16,10 +16,10 @@
 /**
  * Initializes Sprite.
  */
-Player::Player(World& world, Collection& collection, Pathfinder& pathfinder,
+Player::Player(World& world, Pathfinder& pathfinder,
 	const Vector2f& position, const Yaml& config) :
-		Character(world, collection, pathfinder,
-				Data(world, position, 0, CATEGORY_ACTOR, MASK_ALL),
+		Character(world, pathfinder,
+				Data(position, 0, CATEGORY_ACTOR, MASK_ALL),
 				config),
 		mDirection(0) {
 }
diff --git a/source/sprites/Player.h b/source/sprites/Player.h
index e1dde55..58d3742 100644
--- a/source/sprites/Player.h
+++ b/source/sprites/Player.h
@@ -41,7 +41,7 @@ public:
 
 // Public functions.
 public:
-	Player(World& world, Collection& collection, Pathfinder& pathfinder,
+	Player(World& world, Pathfinder& pathfinder,
 			const Vector2f& position, const Yaml& config);
 
 	void setCrosshairPosition(const Vector2f& position);
diff --git a/source/sprites/TileManager.cpp b/source/sprites/TileManager.cpp
index 2084039..e1f8a7c 100644
--- a/source/sprites/TileManager.cpp
+++ b/source/sprites/TileManager.cpp
@@ -32,8 +32,8 @@ TileManager::TileManager(World& world) :
  * @param pPosition Position of the tile in tile coordinates.
  * @param world Box2D world object.
  */
-TileManager::Tile::Tile(Type type, const TilePosition& position, World& world) :
-		Sprite(Yaml(getConfig(type)), Data(world,
+TileManager::Tile::Tile(Type type, const TilePosition& position) :
+		Sprite(Yaml(getConfig(type)), Data(
 				Vector2f(position.x * TILE_SIZE.x, position.y * TILE_SIZE.y), 0,
 				CATEGORY_WORLD, (type == Type::FLOOR) ? MASK_NONE : MASK_ALL)),
 		mType(type) {
@@ -90,7 +90,9 @@ TileManager::setTile(const TilePosition& position, Type type) {
 			mTiles.erase(it);
 		}
 	}
-	mTiles.push_back(std::unique_ptr<Tile>(new Tile(type, position, mWorld)));
+	std::shared_ptr<Tile> tile = std::shared_ptr<Tile>(new Tile(type, position));
+	mTiles.push_back(tile);
+	mWorld.insert(tile);
 }
 
 /**
diff --git a/source/sprites/TileManager.h b/source/sprites/TileManager.h
index 659e4dc..7d22850 100644
--- a/source/sprites/TileManager.h
+++ b/source/sprites/TileManager.h
@@ -54,7 +54,7 @@ private:
 // Private variables.
 private:
 	World& mWorld;
-	std::vector<std::unique_ptr<Tile> > mTiles;
+	std::vector<std::shared_ptr<Tile> > mTiles;
 };
 
 /**
@@ -63,7 +63,7 @@ private:
 class TileManager::Tile : public Sprite {
 // Public functions.
 public:
-	Tile(Type type, const TilePosition& position, World& world);
+	Tile(Type type, const TilePosition& position);
 
 	Type getType() const;
 	TilePosition getTilePosition() const;
diff --git a/source/types/Instances.h b/source/types/Instances.h
deleted file mode 100644
index 8a4bbef..0000000
--- a/source/types/Instances.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * Instances.h
- *
- *  Created on: 04.10.2012
- *      Author: Felix
- */
-
-#ifndef DG_INSTANCES_H_
-#define DG_INSTANCES_H_
-
-#include "../World.h"
-#include "../sprites/TileManager.h"
-#include "../util/Collection.h"
-#include "../util/Pathfinder.h"
-
-class World;
-class Pathfinder;
-class TileManager;
-class Collection;
-
-/**
- * POD class that holds instances of major classes used by other objects.
- */
-struct Instances {
-	Instances() = default;
-	Instances(Pathfinder& p, TileManager& t, Collection& c, World& w) :
-			pathfinder(p), tilemanager(t), collection(c), world(w) {};
-
-	Pathfinder& pathfinder;
-	TileManager& tilemanager;
-	Collection& collection;
-	World& world;
-};
-
-#endif /* DG_INSTANCES_H_ */
diff --git a/source/util/Collection.cpp b/source/util/Collection.cpp
deleted file mode 100755
index c7238fd..0000000
--- a/source/util/Collection.cpp
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * Collection.cpp
- *
- *  Created on: 29.08.2012
- *      Author: Felix
- */
-
-#include "Collection.h"
-
-#include <algorithm>
-
-/**
- * Insert a drawable into the group. Drawables should only be handled with shared_ptr.
- * An object can't be inserted more than once at the same level.
- */
-void
-Collection::insert(std::shared_ptr<Sprite> drawable) {
-	Body::Category cat = drawable->getCategory();
-	auto item = std::find(mDrawables[cat].begin(), mDrawables[cat].end(), drawable);
-	if (item == mDrawables[cat].end()) {
-		mDrawables[cat].push_back(drawable);
-	}
-}
-
-/**
- * Removes a drawable from the group.
- */
-void
-Collection::remove(std::shared_ptr<Sprite> drawable) {
-	for (auto v = mDrawables.begin(); v != mDrawables.end(); v++) {
-		auto item = std::find(v->second.begin(), v->second.end(), drawable);
-		if (item != v->second.end()) {
-			   v->second.erase(item);
-		}
-	}
-}
-
-/**
- * Deletes any sprites which return true for getDelete().
- */
-void
-Collection::checkDelete() {
-	for (auto v = mDrawables.begin(); v != mDrawables.end(); v++) {
-		for (auto item = v->second.begin(); item != v->second.end(); ) {
-			if ((*item)->getDelete()) {
-				item = v->second.erase(item);
-			}
-			else {
-				item++;
-			}
-		}
-	}
-}
-
-/**
- * Draws all elements in the group.
- */
-void
-Collection::draw(sf::RenderTarget& target, sf::RenderStates states) const {
-	for (auto v = mDrawables.begin(); v != mDrawables.end(); v++) {
-		for (auto item : v->second) {
-			target.draw(static_cast<sf::Drawable&>(*item), states);
-		}
-	}
-}
-
diff --git a/source/util/Collection.h b/source/util/Collection.h
deleted file mode 100755
index aebdc81..0000000
--- a/source/util/Collection.h
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * Collection.h
- *
- *  Created on: 29.08.2012
- *      Author: Felix
- */
-
-#ifndef DG_COLLECTION_H_
-#define DG_COLLECTION_H_
-
-#include <map>
-#include <vector>
-
-#include <SFML/Graphics.hpp>
-
-#include "../abstract/Sprite.h"
-
-class Sprite;
-
-/**
- * A collection of sprites, which can be put into different layers.
- *
- * Uses Sprite instead of sf::Drawable to also manage deleting objects.
- * Render order is determined by Physical::Category (higher number on top).
- */
-class Collection : public sf::Drawable {
-// Public functions.
-public:
-	void insert(std::shared_ptr<Sprite> drawable);
-	void remove(std::shared_ptr<Sprite> drawable);
-	void checkDelete();
-
-// Private functions.
-private:
-    void draw(sf::RenderTarget& target, sf::RenderStates states) const;
-
-// Private variables.
-private:
-	std::map<Body::Category, std::vector<std::shared_ptr<Sprite> > > mDrawables;
-};
-
-#endif /* DG_COLLECTION_H_ */