Vietnam War: Operation Jefferson Glenn begins: The United States 101st Airborne Division and the South Vietnamese 1st Infantry Division initiate a new operation in Thừa Thiên–Huế Province.

The Vietnam War was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam and South Vietnam and their allies. North Vietnam was supported by the Soviet Union and China, while South Vietnam was supported by the United States and other anti-communist nations. The conflict was the second of the Indochina wars and a proxy war of the Cold War. The Vietnam War was one of the postcolonial wars of national liberation, a theater in the Cold War, and a civil war, with civil warfare a defining feature from the outset. Direct US military involvement escalated from 1965 until US forces were withdrawn in 1973. The fighting spilled into the Laotian and Cambodian civil wars, which ended with all three countries becoming communist in 1975.