Tuol Sleng Museum in Phnom Penh - a former high school, it was known as the S-21 (“Security Office 21”) during the Khmer Rouge regime between 1975 and 1979. The name Khmer Rouge, which means "Red Khmers," was given to a left-wing Cambodian faction in the 1950s. Led by Pol Pot, it gained control of Cambodia in 1975. And then began one of the century's greatest massacres. Pol Pot declared "Year Zero" and began a radical program to create an idealized agrarian communist society. He crushed social institutions such as banking and religion and emptied cities of their inhabitants. Intellectuals and anyone else seen as standing in the way of the new social order were mercilessly killed, while many of those who escaped execution died from overwork and starvation.

Thousands of pictures of Khmer Rouge victims hang on the museum walls: men, women and children who were duly photographed, then tortured and killed. S-21 was known simply as "konlaenh choul min dael chenh" - "the place where people go in but never come out." Nearly 20,000 people are known to have entered Tuol Sleng; of these only six are known to have survived.

The regulations of the prison were displayed in each cell on a small black board:
1. You must answer accordingly to my questions. Do not turn them away.
2. Do not try to hide the facts by making pretexts of this and that. You are strictly prohibited to contest me.
3. Do not be a fool for you are a chap who dares to thwart the revolution.
4. You must immediately answer my questions without wasting time to reflect.
5. Do not tell me either about your immoralities or the revolution.
6. While getting lashes or electrification you must not cry at all.
7. Do nothing. Sit still and wait for my orders. If there is no orders, keep quiet. When I ask you to do something. You must do it right away without protesting.
8. Do not make pretexts about Kampuchea Krom in order to hide your jaw of traitor.
9. If you don’t follow all the above rules, you shall get many lashes of electric wire.
10. If you disobey any point of my regulations you shall get either ten lashes or five shocks of electric discharge.

The prisoners were required to abide by all of the regulations. To do anything, even to shift their positions while trying to sleep, the inmates had first to ask permission from the prison guards. Anyone breaching these rules was severely beaten.

In fact, most of the victims of Tuol Sleng were actually former Khmer Rouge cadres. With each passing year the regime became more and more paranoid, blaming many of its loyal supporters for Cambodia's woes. The Khmer Rouge leadership saw conspiring enemies around every corner. To exterminate this perceived infestation the Khmer Rouge rounded up hundreds of fellow communists each month, sending them to S-21 in order to extract forced confessions. The methods of extracting confessions at Tuol Sleng were cruel and barbaric. Prisoners were tortured with battery powered electric shocks, searing hot metal prods, knives and other terrifying implements.

The Khmer Rouge was ousted from power by a Vietnamese invasion in 1979. But it had already caused the deaths of between 1.5 million and 2 million people, according to Western estimates. Many victims may never be identified. ( The Legacy of Pol Pot, From Sideshow
To Genocide:Stories of the Cambodian Holocaust)