diff --git a/public/index.php b/public/index.php
index aa06a8a..a4cc7f8 100644
--- a/public/index.php
+++ b/public/index.php
@@ -3,20 +3,23 @@
 require '../main.php';
 
 // very basic routing
-$host = $_SERVER["REQUEST_SCHEME"] . '://' . $_SERVER["SERVER_NAME"];
+$host = $_SERVER['REQUEST_SCHEME'] . '://' . $_SERVER['SERVER_NAME'];
 $url = $_SERVER['REQUEST_URI'];
 if (($pos = strpos($url, '?')) !== false) {
     $url = substr($url, 0, $pos);
 }
 switch($url) {
     case '/game':
-        $controller = new MapGuesser\Controller\GameController();
+        $mapId = isset($_GET['map']) ? (int) $_GET['map'] : 0;
+        $controller = new MapGuesser\Controller\GameController($mapId);
         break;
     case '/game.json':
-        $controller = new MapGuesser\Controller\GameController(true);
+        $mapId = isset($_GET['map']) ? (int) $_GET['map'] : 0;
+        $controller = new MapGuesser\Controller\GameController($mapId, true);
         break;
     case '/position.json':
-        $controller = new MapGuesser\Controller\PositionController();
+        $mapId = isset($_GET['map']) ? (int) $_GET['map'] : 0;
+        $controller = new MapGuesser\Controller\PositionController($mapId);
         break;
     case '/':
         header('Location: ' . $host  . '/game', true, 302);
diff --git a/public/static/js/mapguesser.js b/public/static/js/game.js
similarity index 98%
rename from public/static/js/mapguesser.js
rename to public/static/js/game.js
index e31507e..20a5c4b 100644
--- a/public/static/js/mapguesser.js
+++ b/public/static/js/game.js
@@ -51,7 +51,7 @@
                 Core.startNewRound();
             };
 
-            xhr.open('GET', 'position.json', true);
+            xhr.open('GET', 'position.json?map=' + mapId, true);
             xhr.send();
         },
 
@@ -127,7 +127,7 @@
                 Core.resetGame();
             };
 
-            xhr.open('GET', 'game.json', true);
+            xhr.open('GET', 'game.json?map=' + mapId, true);
             xhr.send();
         },
 
@@ -200,7 +200,7 @@
                 Core.panoId = this.response.panoId;
             };
 
-            xhr.open('POST', 'position.json', true);
+            xhr.open('POST', 'position.json?map=' + mapId, true);
             xhr.send(data);
         },
 
diff --git a/src/Controller/GameController.php b/src/Controller/GameController.php
index 9f38af2..c1174f4 100644
--- a/src/Controller/GameController.php
+++ b/src/Controller/GameController.php
@@ -10,13 +10,13 @@ use MapGuesser\Interfaces\View\IView;
 
 class GameController implements IController
 {
+    private int $mapId;
+
     private bool $jsonResponse;
 
-    // demo map
-    private int $mapId = 1;
-
-    public function __construct($jsonResponse = false)
+    public function __construct(int $mapId, $jsonResponse = false)
     {
+        $this->mapId = $mapId;
         $this->jsonResponse = $jsonResponse;
     }
 
@@ -32,7 +32,7 @@ class GameController implements IController
             ];
         }
 
-        $data = ['bounds' => $bounds->toArray()];
+        $data = ['mapId' => $this->mapId, 'bounds' => $bounds->toArray()];
 
         if ($this->jsonResponse) {
             return new JsonView($data);
diff --git a/src/Controller/PositionController.php b/src/Controller/PositionController.php
index eca8311..cddee8d 100644
--- a/src/Controller/PositionController.php
+++ b/src/Controller/PositionController.php
@@ -13,8 +13,12 @@ class PositionController implements IController
     const NUMBER_OF_ROUNDS = 5;
     const MAX_SCORE = 1000;
 
-    // demo map
-    private int $mapId = 1;
+    private int $mapId;
+
+    public function __construct(int $mapId)
+    {
+        $this->mapId = $mapId;
+    }
 
     public function run(): IView
     {
@@ -120,7 +124,7 @@ class PositionController implements IController
         $select->where('id', 'NOT IN', $exclude);
         $select->where('map_id', '=', $this->mapId);
 
-        $numberOfPlaces = $select->count();
+        $numberOfPlaces = $select->count();// TODO: what if 0
         $randomOffset = random_int(0, $numberOfPlaces - 1);
 
         $select->orderBy('id');
diff --git a/src/Util/Geo/Bounds.php b/src/Util/Geo/Bounds.php
index 7b448be..1edfb8b 100644
--- a/src/Util/Geo/Bounds.php
+++ b/src/Util/Geo/Bounds.php
@@ -4,21 +4,25 @@ class Bounds
 {
     const ONE_DEGREE_OF_LATITUDE_IN_METER = 111132.954;
 
-    private float $southLat;
-    private float $westLng;
+    private float $southLat = 90.0;
+    private float $westLng = 180.0;
 
-    private float $northLat;
-    private float $eastLng;
+    private float $northLat = -90.0;
+    private float $eastLng = -180.0;
 
-    private bool $initialized = false;
-
-    public static function createWithPosition(Position $position): Bounds
+    public function __construct(Position $position = null)
     {
-        $instance = new static();
+        if ($position === null) {
+            return;
+        }
 
-        $instance->initialize($position);
+        $lat = $position->getLat();
+        $lng = $position->getLng();
 
-        return $instance;
+        $this->northLat = $lat;
+        $this->westLng = $lng;
+        $this->southLat = $lat;
+        $this->eastLng = $lng;
     }
 
     public static function createDirectly(float $southLat, float $westLng, float $northLat, float $eastLng): Bounds
@@ -30,19 +34,11 @@ class Bounds
         $instance->northLat = $northLat;
         $instance->eastLng = $eastLng;
 
-        $instance->initialized = true;
-
         return $instance;
     }
 
     public function extend(Position $position): void
     {
-        if (!$this->initialized) {
-            $this->initialize($position);
-
-            return;
-        }
-
         $lat = $position->getLat();
         $lng = $position->getLng();
 
@@ -77,10 +73,6 @@ class Bounds
 
     public function toArray(): array
     {
-        if (!$this->initialized) {
-            throw new \Exception("Bounds are not initialized!");
-        }
-
         return [
             'south' => $this->southLat,
             'west' => $this->westLng,
@@ -93,17 +85,4 @@ class Bounds
     {
         return json_encode($this->toArray());
     }
-
-    private function initialize(Position $position)
-    {
-        $lat = $position->getLat();
-        $lng = $position->getLng();
-
-        $this->northLat = $lat;
-        $this->westLng = $lng;
-        $this->southLat = $lat;
-        $this->eastLng = $lng;
-
-        $this->initialized = true;
-    }
 }
diff --git a/views/game.php b/views/game.php
index fee7284..49447d3 100644
--- a/views/game.php
+++ b/views/game.php
@@ -48,9 +48,10 @@
         </div>
     </div>
     <script>
+        var mapId = '<?= $mapId ?>';
         var mapBounds = <?= json_encode($bounds) ?>;
     </script>
     <script src="https://maps.googleapis.com/maps/api/js?key=<?= $_ENV['GOOGLE_MAPS_JS_API_KEY'] ?>"></script>
-    <script src="static/js/mapguesser.js"></script>
+    <script src="static/js/game.js"></script>
 </body>
 </html>