Fall of Saigon (1975)
The last American troops left in March 1973, but what some described as a "post-war war" continued.
Southern and northern forces accused each other of breaking the terms of the truce and fighting continued, although it was less intense and casualties were lower than in previous years.
American aid to south Vietnam decreased and the southern government became progressively weaker.
In early March 1975, buoyed by a successful operation at the start of the year, Hanoi launched the first phase of an offensive to take the whole country.
The south Vietnamese army crumbled faster than expected, and in seven weeks communist forces had swept through the south taking the central highlands and the east coast. Millions of refugees fled towards Saigon.
On 21 April, with the NVA closing in on Saigon, the South Vietnamese President Nguyen Van Thieu resigned and fled to Taiwan, railing tearfully against the US.
Six days later the city was surrounded. The NVA began launching shells into civilian areas. Looting broke out.
On 29 April the US ordered the helicopter evacuation of 7,000 American administrators and South Vietnamese from the city. Refugees battled to join the exodus.
The following day, NVA tanks drove unopposed into central Saigon. The city was renamed Ho Chi Minh City.
In the wake of the NVA victory, hundreds of thousands of south Vietnamese who had opposed the communists fled by boat, fearing reprisals.
They formed the first wave of Vietnamese boat people – others followed in 1978 fleeing communist economic reforms.