This place has been the main prison of the former East German Communist Ministry of State Security, the Stasi. In its history this area was in the beginning an industrial area, then a war prison at the end of the WWII (with the name of Special Camp No. 3) with very low living condition.
In 1951 it was renewed and reopened by the Stasi, but it was not mentioned in the official maps of East-Berlin (at its place, there was just a blank area, surroundend by the appartments of the people working in the prison). The prison was primarily used to house those who wished or attempted to leave the GDR, although political prisons were also held there.
Tortures and psychological intimidation was the main method of political repression, and techniques including sleep deprivation, total isolation, threats to friends and family members, and the use of water cells.
I've visited the place with a German guide (who was prisoner there), with germans and no tourists and although it can be very strong as experience, i found it the best way of visiting it.
More info: WIKI
Special thanks to Alexandra Jasper
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