Many artists, including musicians, writers, and filmmakers were executed. Some like Ros Serey Sothea, Pen Ran, and Sinn Sisamouth gained posthumous fame for their talents and are still popular with Khmers today. Ethnic Vietnamese, ethnic Chinese, ethnic Thai and other minorities in Eastern Highland, Cambodian Christians (most of whom were Catholic, and the Catholic Church in general), Muslims and the Buddhist monks. "Economic saboteurs:" many of the former urban dwellers (who had not starved to death in the first place) were deemed to be guilty by virtue of their lack of agricultural ability. Through the 1970s, and especially after mid-1975, the party was also shaken by factional struggles. There were even armed attempts to topple Pol Pot. The resultant purges reached a crest in 1977 and 1978 when thousands, including some important KCP leaders, were executed. Today, examples of the torture methods used by the Khmer Rouge can be seen at the Tuol Sleng Genocide Museum. The museum occupies the former grounds of a high school turned prison camp that was operated by Comrade Duch. The torture system at Tuol Sleng was designed to make prisoners confess to whatever crimes they were charged with by their captors. In their confessions, the prisoners were asked to describe their personal backgrounds. If they were party members, they had to say when they joined the revolution and describe their work assignments in DK. Then the prisoners would relate their supposed treasonous activities in chronological order. The third section of the confession text described prisoners' thwarted conspiracies and supposed treasonous conversations. In the end, the confessions would list a string of traitors who were the prisoners' friends, colleagues, or acquaintances. Some lists contained over a hundred names. People whose names were on the confession list were often called in for interrogation. Typical confessions ran into thousands of words in which the prisoner would interweave true events in their lives with imaginary accounts of their espionage activities for the CIA, the KGB, or Vietnam. 17,000 people passed through Security Prison 21 (now the Tuol Sleng Genocide Museum), before they were taken to sites (also known as the Killing Fields), outside Phnom Penh such as Choeung Ek where most were executed (often with pickaxes, to save bullets) and buried in mass graves. Of the thousands who entered Tuol Sleng only twelve are known to have survived. Explaining the violence Violence as a collective action While the