Tuol Sleng Genocide Museum is the memorial site of “Security Office 21” (S-21) of Democratic Kampuchea (also known as the Khmer Rouge regime) and located in what was then the abandoned city of Phnom Penh, whose citizens had been evacuated on 17. April 1975.

S-21 served as the central hub of a vast prison system throughout the country and was used throughout the period as a secret facility for the detention, interrogation, torture and extermination of those deemed “political enemies” of the regime. Due to a policy of guilt-by-association, at times whole families were detained at the center. Very few inmates were released out of the prison during the years 1975 and 1979. Only 12 former inmates survived the opening of S-21 when Phnom Penh was liberated. Four of them were children.

Approximately 1,720 Khmer Rouge actors worked in and for S-21. Several hundred of them were general workers, including people who grew food for the prison. The rest formed the internal workforce, including administration, guards and interrogators.