On April 29, 1975, as communist North Vietnamese troops closed in on the South Vietnamese capital of Saigon, the United States ordered the immediate evacuation of U.S. personnel and several thousand South Vietnamese military and diplomatic officials. TV news cameras broadcasted harrowing images of the chaotic airlift, including crowds of desperate South Vietnamese citizens swarming the gates of the American Embassy in Saigon, soon to be renamed Ho Chi Minh City by the conquering communists.

The swift fall of Saigon in 1975 signaled the end of America’s failed military intervention in Southeast Asia, but it only marked the beginning of what would become one of the largest and longest refugee crises in history.

Over the next two decades—from 1975 to 1995—more than three million people fled Vietnam, Laos and Cambodia. Countless thousands died at sea, victims of pirates or overcrowded, makeshift boats. The lucky ones made it to refugee camps in Thailand, Malaysia or the Philippines, and more than 2.5 million refugees were eventually resettled around the world, including more than a million in the United States.

In the months following the fall of Saigon, U.S President Gerald Ford and Congress authorized the evacuation and resettlement in the United States of approximately 140,000 refugees from South Vietnam and Cambodia. But there were many hundreds of thousands more, including former members of the South Vietnamese army and their families, who faced torture and retribution from the ruling North Vietnamese.

“A common sight at the end of the war was to see South Vietnamese soldiers burning their uniforms, making sure they had no affiliation with the military whatsoever,” says Phuong Tran Nguyen, a history professor at California State University, Monterey Bay, and author of Becoming Refugee American: The Politics of Rescue in Little Saigon.

South Vietnamese intellectuals and other potential enemies of the revolution were rounded up and shipped off to “reeducation” camps, which were really forced labor camps designed to break the will of the South Vietnamese and indoctrinate them with communist ideologies. Many residents of Saigon, the former South Vietnamese capital, were forced to move to the countryside to labor on collective farms. In neighboring Cambodia, the Khmer Rouge seized power and began a brutal campaign of imprisonment and mass executions of its enemies.

As the political and economic situations deteriorated in Vietnam, Laos and Cambodia, the steady trickle of refugees fleeing the region became a torrent. Desperate families packed their belongings in a single suitcase and fled their homes “by any means available,” says Long Bui, a professor of international studies at the University of California Irvine and author of Returns of War: South Vietnam and the Price of Refugee Memory.

“Some of them trekked through the forest through Laos and into Thailand, but mostly they fled by ocean to places like Singapore and Hong Kong,” says Bui. “They were often attacked by Malaysian and Thai pirates who raped the women and stole any gold or money they had. That’s why it was so harrowing.”

These “boat people,” as the refugees became known, weren’t welcomed or even recognized as refugees by most countries in the region. None of the nations in Southeast Asia had signed on to the United Nations Refugee Convention, for example, and some were openly hostile to the tens of thousands of Vietnamese and Cambodians who were threatening to overwhelm their limited resources. By 1979, when more than 50,000 refugees were arriving by boat every month, countries like Malaysia and Singapore began physically pushing boats full of refugees back into the sea.

“It’s estimated that between 25,000 and 50,000 boat people perished at sea,” says Nguyen. “They were out for days without almost any food or water, and a lot of the women and children couldn't swim.”