And yess we have 3 Winners.. (I count the first guess from Jim Rae as one of them as his first guess was the closest.)
Then comes CReading. Also for his guess of the Flaktower. But a big Bravo goes to Davester as he gave the exact information about the little portion you could see in the pictures.
It is indeed the Humboldthain Flaktower(Turm) G. As CReading already said the fencing is postwar as is the monument standing on left tower.
Here are some more pictures of this collosal building
First the picture of which I took the portion out
Well I spend around 20 minutes walking through the Humboldthain public park and guess what I couldn`t find the tower. It really is something you can miss ain`t it. They blew up the whole back part which is now a huge pile of rubble only the north side stands up