diff --git a/Camera2D.gd b/Camera2D.gd
index b2748a9..93563e1 100644
--- a/Camera2D.gd
+++ b/Camera2D.gd
@@ -26,9 +26,7 @@ func build_tower():
 	last_built += tower_density
 
 func build_all_towers():
-	while towers.size() > 0:
-		towers.pop_back().queue_free()
-
+	get_tree().call_group("tower", "queue_free")
 	last_built = 300
 	while last_built < screen_size.x * 3:
 		build_tower()
@@ -44,5 +42,4 @@ func _ready():
 	randomize()
 
 func _on_Tower_exit():
-	towers.pop_front()
 	build_tower()
diff --git a/Tower.gd b/Tower.gd
index 3f41ef7..cb49cc6 100644
--- a/Tower.gd
+++ b/Tower.gd
@@ -5,6 +5,7 @@ signal passed
 
 # Called when the node enters the scene tree for the first time.
 func _ready():
+	add_to_group("tower")
 	pass # Replace with function body.
 
 func _on_Tower_body_entered(body):
diff --git a/UI.gd b/UI.gd
index afd5813..c793eaf 100644
--- a/UI.gd
+++ b/UI.gd
@@ -30,7 +30,3 @@ func _on_Player_passed():
 func update_ui():
 	best_score.text = "Best: "+str(best)
 	current_score.text = "Current: "+str(current)
-
-# Called every frame. 'delta' is the elapsed time since the previous frame.
-#func _process(delta):
-#	pass