India, May 2 -- US helicopters landed on Saigon rooftops and at Tan Son Nhut airbase on April 29, 1975, and began evacuating all but a handful of more than 900 Americans left in the city as the South Vietnamese capital awaited the National Liberation Front forces. The next day, the National Liberation Front and North Vietnamese forces occupied Saigon following the unconditional surrender of its government, putting an end to nearly 30 years of war in Vietnam. US fighter-bombers flew high over the besieged city, providing air cover for the evacuation. Officials said the US embassy would close soon, ending three decades of official involvement in the war in the Indo-China region. Three US Marine helicopters landed at the US defence attache's c...