End of South Vietnam; Communist North Vietnam annexes the former South Vietnam to form the unified Socialist Republic of Vietnam.

The Provisional Revolutionary Government of the Republic of South Vietnam, was formed on 8 June 1969, by the Democratic Republic of Vietnam as an armed rival government opposing the government of the Republic of Vietnam under President Nguyễn Văn Thiệu. Delegates of the National Liberation Front of South Vietnam, as well as several smaller groups, participated in its creation.

North Vietnam, officially the Democratic Republic of Vietnam, was a country in Southeast Asia from 1945 to 1976, with sovereignty fully recognized in 1954. A member of the communist Eastern Bloc, it opposed the French-supported State of Vietnam and later the Western-allied Republic of Vietnam. The DRV invaded Saigon in 1975 and ceased to exist the following year when it merged with the south to become the current Socialist Republic of Vietnam.

South Vietnam, officially the Republic of Vietnam, was a country in Southeast Asia that existed from 1955 to 1975. It first garnered international 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. South Vietnam was bordered by North Vietnam to the north, Laos to the northwest, Cambodia to the southwest, and Thailand across the Gulf of Thailand to the southwest. Its sovereignty was recognized by the United States and 87 other nations, though it failed to gain admission into the United Nations as a result of a Soviet veto in 1957. It was succeeded by the Republic of South Vietnam in 1975. In 1976, the Republic of South Vietnam and North Vietnam merged to form the Socialist Republic of Vietnam.

Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about 331,000 square kilometres (128,000 sq mi) and a population of over 100 million, making it the world's fifteenth-most populous country. One of two communist states in Southeast Asia, Vietnam shares land borders with China to the north, and Laos and Cambodia to the west. Its capital is Hanoi and its largest city is Ho Chi Minh City.