Berlin-Hohenschönhausen Stasi Prison Complex Museum, Lichtenberg, Berlin, Germany

Although torture (including Chinese water torture) and physical violence were commonly employed at Hohenschönhausen (especially in the 1950s), 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.
A suggested reason why the torture of East Germany's own citizenry was permitted for so long was Hohenschönhausen exclusion zone. The prison was located in a large restricted area bordered by a large military town. Additionally, it officially did not exist during many of the year it operated, being left off all maps. These two measures combined meant that few people who did not work there know what occurred inside. Because it was not well known, the prison was not stormed by demonstrators after the fall of the Wall. This allowed prison authorities to destroy much of the evidence of their crimes. Today, much of our knowledge comes from former prisoners personal accounts and documentation from other GDR institutions.