I found this place near the hostel I stayed at in Hamburg, Germany this summer. After breakfast, I snooped around a bit and wound up getting a tour. It turned out to be an old theatre, or what's left of it. I wasn't allowed to take any pictures inside, unfortunately. For the most part it was similarly tagged on the inside. The squatters have stabilized the structure, put in electricty and working plumbing and a waterproof roof. The stage and seating area were completely demolished years ago, leaving only the lobby portion which was taken over by squatters a decade or so ago. It now hosts music practice space and artist studios for about 300 people. Nobody is allowed to live there, and it comprises three floors counting the basement. The city tries to tear it down every few years, but the squatters always counter with a petition.