The Bunker was used by the Nazis in the Second World War. A U-boat has been abandoned in the central dock, and there are rooms and corridors either side. The corridors are filled with pipes and cranks, and by the time Nate gets there the electricity is failing and the place is wrecked. There are two over hanging communication rooms, only one of which has a microphone. Anyone standing in them have full view of the Bunker.
The Bunker had become infested with Descendants, who had attacked and killed the Nazis.