Zombie Graben

Zombie Graben (German for Zombie Trench) is a zombie map found in the game files of Call of Duty: Black Ops. It would be based on the campaign mission "S.O.G.", with the trenches returning. Also, several underground bunkers appear, exclusive to this map. Nazi Zombies return in this, so it is possible that it was to originally be in World at War, but this is unconfirmed.