On January 7, 1979, Vietnamese troops seize the Cambodian capital of Phnom Penh, toppling the brutal regime of Pol Pot and his Khmer Rouge.

The Khmer Rouge, organized by Pol Pot in the Cambodian jungle in the 1960s, advocated a radical Communist revolution that would wipe out Western influences in Cambodia and set up a solely agrarian society. In 1970, aided by North Vietnamese and Viet Cong troops, Khmer Rouge guerrillas began a large-scale insurgency against Cambodian government forces, soon gaining control of nearly a third of the country.

By 1973, secret U.S. bombings of Cambodian territory controlled by the Vietnamese Communists forced the Vietnamese out of the country, creating a power vacuum that was soon filled by Pol Pot’s rapidly growing Khmer Rouge movement. In April 1975, the Khmer Rouge captured Phnom Penh, the Cambodian capital, overthrew the pro-U.S. regime, and established a new government, the Kampuchean People’s Republic.

As the new ruler of Cambodia, Pol Pot set about transforming the country into his vision of an agrarian utopia. The cities were evacuated, factories and schools were closed, and currency and private property was abolished. Anyone believed to be an intellectual, such as someone who spoke a foreign language, was immediately killed. Skilled workers were also killed, in addition to anyone caught in possession of eyeglasses, a wristwatch, or any other modern technology. In forced marches punctuated with atrocities from the Khmer Rouge, the millions who failed to escape Cambodia were herded onto rural collective farms.

Between 1975 and 1978, an estimated two million Cambodians died by execution, forced labor, and famine. In 1978, Vietnamese troops invaded Cambodia, capturing Phnom Penh in early 1979. A moderate Communist government was established, and Pol Pot and the Khmer Rouge retreated back into the jungle.

In 1985, Pol Pot officially retired but remained the effective head of the Khmer Rouge, which continued its guerrilla actions against the government in Phnom Penh. In 1997, however, he was put on trial by the organization after an internal power struggle ousted him from his leadership position. Sentenced to life imprisonment by a “people’s tribunal,” which critics derided as a show trial, Pol Pot later declared in an interview, “My conscience is clear.” Much of the international community hoped that his captors would extradite him to stand trial for his crimes against humanity, but he died of apparently natural causes while under house arrest in 1998.