Tuol Sleng Genocide Museum ( ) is a museum in Phnom Penh , the capital of Cambodia , chronicling the Cambodian genocide . The site is a former secondary school which was used as Security Prison 21 ( S-21 ) by the Khmer Rouge regime from its rise to power in 1975 to its fall in 1979 . From 1976 to 1979 , an estimated 20,000 people were imprisoned at Tuol Sleng ( the real number is unknown ) . Tuol Sleng ( ) means " Hill of the Poisonous Trees " or " Strychnine Hill " . Tuol Sleng was just one of at least 150 torture and execution centers established by the Khmer Rouge , though other sources put the figure at 196 prison centers . On July 26 , 2010 , the Extraordinary Chambers in the Courts of Cambodia convicted the chief of Tuol Sleng Prison , Kang Kek Iew , ( alias Duch ) for crimes against humanity and grave breaches of the 1949 Geneva Conventions and sentenced him to life imprisonment
Cambodian genocide
Cambodian genocide
Tuol Sleng Genocide Museum