The Tuol Sleng genocide museum in Phnom Penh is a grim memorial to one of the darkest chapters in Cambodian history. Built in 1962 as Tuol Svay Prey High School, the site was transformed in 1976 by the Khmer Rouge regime into Security Prison 21 (S-21), a center for the detention, interrogation, torture and extermination of suspected political enemies during their reign from 1975 to 1979.
