diff --git a/OpenRa.Game/Shroud.cs b/OpenRa.Game/Shroud.cs
index b3a9e0adc2..8943aaa216 100644
--- a/OpenRa.Game/Shroud.cs
+++ b/OpenRa.Game/Shroud.cs
@@ -137,7 +137,7 @@ namespace OpenRa
 
 		internal void Draw(SpriteRenderer r)
 		{
-			return;
+			return;	// temp; just so i can see until i'm done with the bridges.
 
 			if (dirty)
 			{
diff --git a/OpenRa.Game/Traits/Bridge.cs b/OpenRa.Game/Traits/Bridge.cs
index e626e2c93d..43b5b5635a 100644
--- a/OpenRa.Game/Traits/Bridge.cs
+++ b/OpenRa.Game/Traits/Bridge.cs
@@ -12,11 +12,11 @@ namespace OpenRa.Traits
 		public object Create(Actor self) { return new Bridge(); }
 	}
 
-	class Bridge : IRender, ITick
+	class Bridge : IRender, ITick, ICustomTerrain
 	{
 		Animation anim;
-
-		public Bridge() {}
+		Dictionary<int2, int> Tiles;
+		TileTemplate Template;
 
 		public IEnumerable<Renderable> Render(Actor self)
 		{
@@ -37,7 +37,18 @@ namespace OpenRa.Traits
 
 		public void SetTiles(TileTemplate template, Dictionary<int2, int> replacedTiles)
 		{
-			/* todo: stash these, etc */
+			Template = template;
+			Tiles = replacedTiles;
+
+			foreach (var t in replacedTiles.Keys)
+				Game.world.customTerrain[t.X, t.Y] = this;
+		}
+
+		public double GetCost(int2 p, UnitMovementType umt)
+		{
+			var origTile = Tiles[p];	// if this explodes, then SetTiles did something horribly wrong.
+
+			return 1.0;
 		}
 	}
 }
diff --git a/OpenRa.Game/Traits/TraitsInterfaces.cs b/OpenRa.Game/Traits/TraitsInterfaces.cs
index cc7afc4569..51f401d358 100644
--- a/OpenRa.Game/Traits/TraitsInterfaces.cs
+++ b/OpenRa.Game/Traits/TraitsInterfaces.cs
@@ -25,6 +25,8 @@ namespace OpenRa.Traits
 	public interface IAcceptThief { void OnSteal(Actor self, Actor thief); }
 	public interface IAcceptSpy { void OnInfiltrate(Actor self, Actor spy); }
 
+	public interface ICustomTerrain { double GetCost(int2 p, UnitMovementType umt); }
+
 	interface IProducer
 	{
 		bool Produce( Actor self, ActorInfo producee );
diff --git a/OpenRa.Game/World.cs b/OpenRa.Game/World.cs
index bd68474af9..26e46e35e7 100644
--- a/OpenRa.Game/World.cs
+++ b/OpenRa.Game/World.cs
@@ -4,6 +4,7 @@ using OpenRa.Effects;
 using OpenRa.Support;
 using OpenRa.FileFormats;
 using OpenRa.Graphics;
+using OpenRa.Traits;
 
 namespace OpenRa
 {
@@ -21,6 +22,9 @@ namespace OpenRa
 		public readonly Map Map;
 		public readonly TileSet TileSet;
 
+		// for tricky things like bridges.
+		public readonly ICustomTerrain[,] customTerrain = new ICustomTerrain[128, 128];
+
 		public readonly WorldRenderer WorldRenderer;
 		internal readonly Minimap Minimap;