South Vietnamese president Ngô Đình Diệm (pictured) was arrested and assassinated in Saigon, marking the culmination of a coup d'état led by Dương Văn Minh.

The Republic of Vietnam, commonly known as South Vietnam, was a country in Southeast Asia that existed from 1955 to 1975. It first garnered recognition in 1949 as the associated State of Vietnam within the French Union, with its capital at Saigon. Since 1950, it was a member of the Western Bloc during the Cold War. Following the 1954 partition of Vietnam, it became known as South Vietnam and was established as a republic in 1955. Although South Vietnam failed to gain admission into the United Nations as a result of a Soviet veto in 1957, its sovereignty was recognized by 95 countries as of January 1975. It was succeeded by the communist-controlled Republic of South Vietnam in 1975. In 1976, North Vietnam and the Republic of South Vietnam merged to form the Socialist Republic of Vietnam.