Pol Pot (1925-1998) and his communist Khmer Rouge movement led Cambodia from 1975 to 1979. During that time, about 1.5 million Cambodians out of a total population of 7 to 8 million died of starvation, execution, disease or overwork. Some estimates place the death toll even higher. One detention center, S-21, was so notorious that only seven of the roughly 20,000 people imprisoned there are known to have survived. The Khmer Rouge, in their attempt to socially engineer a classless peasant society, took particular aim at intellectuals, city residents, ethnic Vietnamese, civil servants and religious leaders. An invading Vietnamese army deposed the Khmer Rouge in 1979, and, despite years of guerilla warfare, they never took power again. Pol Pot died in 1998 without ever being brought to justice.