Under the leadership of Pol Pot and his comrades, the Khmer Rouge, a repressive and totalitarian communist regime, killed an estimated 1.7 million Cambodians through starvation, overwork, torture and execution between 1975 and 1979. One of the worst atrocities in a century riddled with large-scale atrocities, the genocide in Cambodia stemmed from an intellectual Marxist elite trained at the University of Paris and committed to an extreme form of social engineering. Pol Pot sought to reverse the clock of "bourgeois" influence, create a Year Zero, and forcefully return the country to a pre-modern agrarian society. Pictured are some of the rank-and-file Khmer Rouge killers.