Final answer:
Vietnam was divided into Communist North Vietnam and capitalist South Vietnam after French Indochina's decolonization, leading to the Vietnam War which ended with the fall of Saigon and reunification under communist rule in 1975.
Step-by-step explanation:
The division of Vietnam into North and South Vietnam was a significant outcome of the Cold War geopolitics and the decolonization of French Indochina.
The ideological divide between the North and South eventually escalated into the Second Indochina War, commonly known as the Vietnam War, beginning in 1959. The North aimed to unify Vietnam under a Communist regime, while the South stood against this, leading to a protracted conflict that drew in international forces, most notably the United States. Despite receiving substantial foreign aid and military support, South Vietnam eventually fell to the North Vietnamese forces. In 1975, the fall of Saigon to the North Vietnamese Army marked the end of the war and the start of the country's reunification under communist rule.