Before my vacation, I didn't get the chance to post the rest of the photos from our tour of the Blavand part of Hitler's North Atlantic Wall - a lapse I will make up to you with this post now :)
What you see here is what reamins of the "Mammut-Stellung" (Mammoth-Emplacement).
This was a command bunker of the Luftwaffe with a huge long-range radar array on top of it. You can find more information on the type of radar used here.
There are two towers on top of the bunker (you can't see the second one because of the angle). These were the foundation for the radar array and contained the cable shafts that led to the control room.