Monk Thích Quảng Đức burns himself to death in Saigon in protest at the Diệm government's treatment of Buddhists; the photograph shocks the world.
A smaller Viet Cong force repels an attack by South Vietnamese troops with US advisers near Mỹ Tho.
Malaya unites with Singapore, Sabah (North Borneo) and Sarawak to form Malaysia.
Generals led by Dương Văn Minh overthrow President Ngô Đình Diệm, who is killed with his brother Ngô Đình Nhu the next day.
The US Air Force sprays herbicides, including dioxin-contaminated Agent Orange, over large areas of South Vietnam, with lasting health and environmental effects.
A clash between USS Maddox and North Vietnamese torpedo boats leads Congress to pass the Gulf of Tonkin Resolution, enabling US escalation.
After the failed 30 September Movement coup, the army and militias kill hundreds of thousands of alleged communists, paving the way for Suharto's rise.