Tuol Sleng Genocide Museum

The Tuol Sleng Genocide Museum () is a museum in Phnom Penh, the capital of Cambodia. It talks about 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, about 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 created by the Khmer Rouge. 
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.