Tuol Sleng Genocide Museum

Tuol Sleng was a secondary school in Phnom Penh until 1976, when the Khmer Rouge converted it into Security Prison 21, one of the regime's most notorious interrogation centers. An estimated 20,000 people passed through its converted classrooms between 1976 and 1979; prison records suggest only a handful survived. Rooms still contain iron bed frames, shackles, and thousands of black-and-white photographs the regime took of each prisoner on arrival, their expressions frozen in the moment before years of documented torture. Since it opened as a museum in 1980, staff and visitors have described an atmosphere many call inescapably heavy — a persistent cold in certain rooms, and a widespread, unverifiable sense reported by guides that the photographed eyes seem to follow visitors through the halls. Whether or not one credits any of that to the paranormal, S-21 remains one of the most solemn sites connected to the Cambodian genocide, formally documented in the 2010 conviction of its commandant, Kang Kek Iew.