The correct answer is Saigon.
The Fall or the Liberation of Saigon was the capture of the city of Saigon, the capital of South Vietnam. The city was captured by the People's Army of Vietnam and the Viet Cong on April 30th, 1975.
The capture of Saigon was preceded by Operation Frequent Wind, which was the evacuation of almost all American civilians and military personnel in Saigon, along with thousands of South Vietnamese civilians. This was the largest helicopter evacuation in history.
The Fall of Saigon was the start of the transition period which led to the unification of both parts of Vietnam into the Socialist Republic of Vietnam.
