Khmer Rouge guerrillas marched into Phnom Penh and forced the surrender of the Cambodian government, ending five years of civil war. Within days, the new regime began forcibly evacuating the capital's two million residents to the countryside, launching a radical agrarian revolution that led to the deaths of an estimated 1.7 to 2 million Cambodians through execution, starvation, and forced labor.
Residents initially greeted the black-clad Khmer Rouge soldiers with relief, believing the war was finally over. That relief lasted only hours. Within a day, soldiers began ordering the entire population of Phnom Penh, then swollen with wartime refugees to nearly two million people, to evacuate on foot, telling them American bombers were coming and the evacuation would last only a few days.
It was a lie. The evacuation was the opening act of Year Zero, Pol Pot's plan to remake Cambodia into an agrarian utopia purged of cities, money, religion, and Western influence. Doctors, teachers, monks, and anyone wearing glasses or speaking a foreign language became targets. Hospitals were emptied mid-surgery, patients forced onto the roads.
Over the next three years, eight months, and twenty days, the Khmer Rouge would kill or starve to death close to a quarter of Cambodia's population, one of the deadliest genocides per capita in modern history. The killing fields at Choeung Ek and the prison at Tuol Sleng became lasting symbols of the horror. It was Vietnamese forces, invading in late 1978, that finally toppled the regime, but the trauma inflicted on Cambodian society during those 44 months would take generations to address.