Tuol Sleng Genocide Museum

Tuol Sleng Genocide Museum occupies the former Chao Ponhea Yat High School, which was converted by the Khmer Rouge into Security Prison 21, or S-21, between 1975 and 1979. During that period it served as the regime's most notorious detention and interrogation facility, where an estimated 17,000 men, women, and children were imprisoned and tortured before being taken to Choeung Ek for execution. Only a handful of prisoners survived. Today the site preserves classrooms converted into cells, barbed wire barriers, and thousands of prisoner photographs and confession documents. The museum provides essential historical context about the Khmer Rouge regime through exhibitions, survivor testimonies, and guided tours, and stands as one of the most sobering and important memorials in Southeast Asia.