South Vietnam, officially known as the Republic of Vietnam, existed from 1955 until 1975. It was established during the Cold War as a separate state in the southern part of Vietnam, opposing the communist North. The capital was Saigon, which became a significant center for American military and political efforts during the Vietnam War. The region was marked by conflict, social upheaval, and significant U.S. involvement. After years of fighting, South Vietnam fell to North Vietnamese forces in 1975, leading to the reunification of Vietnam under communist control. This event had lasting impacts on the region and the world.