Tuol Sleng Genocide Museum
The Tuol Sleng Genocide Museum is a museum for the Cambodian genocide. Located in Phnom Penh, the site is a former secondary school that had been turned into an internment facility known as Security Prison 21 (S-21) by the Khmer Rouge regime from 1975 until its fall in 1979.
Source: Wikipedia — Tuol Sleng Genocide Museum (CC BY-SA 4.0)