The black-and-white photo of the helicopter perched on a Saigon rooftop, awaiting a stream of refugees to be airlifted, became a powerful visual metaphor for the haphazard American conduct of the war — and its haphazard retreat at its conclusion. Part of the chaos can be accounted for by the surprising quickness of the North Vietnamese advance after the American withdrawal. The South Vietnamese army (ARVN), despite American training and supplies, were overran swiftly. But part does lie with U.S. intelligence, who disastrously overestimated ARVN capabilities, and forced a mass evacuation against the incoming NVA approeach.

On this day, April 30, in 1975 the South Vietnamese capitol of Saigon fell to the North Vietnamese. A massive tide of South Vietnamese refugees preceded it.

The U.S. prioritized evacuating their own civilian staff, taking out all but 1,250 — about the size that could be picked by an airlift within hours’ notice — in March. South Vietnamese applying for visas were also rubber-stamped and approved. Several thousand Vietnamese orphans were taken out via “Operation Babylift.” And those who did not want to wait for U.S. exit approval went through their own routes, chartering boats and planes, often at exorbitant prices.