During the second world war, Hohenschönhausen was a heavily bombed industrial area in the northeast of Berlin.
In 1945, one of the few still intact buildings was used by the Soviet Secret Police as Special Camp 3, a prison camp to intern Nazis and other undesired elements.
The pictures above are from the former cafeteria, converted into prison cells by forced labor.
In 1951, the East German Stasi took over and added a new building with nicer rooms.
It was used as a highly secret interrogation prison, with few people knowing about its existence. Dissidents and other people stubbornly seeking to leave the young republic were brought here into solitary confinement to solicit confessions.
At night, prisoners were checked on every few minutes and woken up if their sleeping position in bed deviated from the norm. The sound of the keyhole latches is still causing nightmares to the survivors.
The psychological torture aimed to make the prisoners feel utterly alone, disoriented, and hopeless.
An open door became even more terrifying than a closed one.