1 of 5 On 31 March 1965, the first US combat troops arrived in Vietnam. By the end of the year, 180,000 troops had been sent, mostly as draftees.
2 of 5 Despite overwhelming airpower, the US became bogged down in a guerrilla war. The Vietcong used tunnels and booby traps to launch surprise attacks. They did not wear uniforms in order to blend in with civilians.
3 of 5 Vietnam was the first television war. Colour images of carpet bombing, napalm victims and American body bags (some 45,000 Americans had died by the end of 1969) led to mass protests against the war.
4 of 5 A peace deal was agreed in 1973 allowing US President Richard Nixon and his right hand man, Dr Henry Kissinger to withdraw American troops. (Up to 500,000 US troops had been deployed in Vietnam.)
5 of 5 Despite promises of support, the United States failed to intervene in 1975 when North Vietnamese forces overran South Vietnam and seized the capital Saigon. It was renamed Ho Chi Minh City after the North's communist leader.