March 29 is national Vietnam Veterans Day.
On March 29, 1973, the last United States combat troops left South Vietnam, ending America's direct military involvement in the Vietnam War.
Remaining American prisoners of war held in North Vietnam were freed.
But, fighting continued.
A peace agreement had been signed in January 1973 in Paris, effectively ending direct U.S. involvement in the Vietnam War, according to www.history.com.
Even before U.S. soldiers left the communists violated the cease-fire agreement. According to history.com, "full-scale war had resumed" by early 1974.
The last few Americans still in South Vietnam were airlifted out April 30, 1975, when Saigon fell to the communists.