What started it?
The Vietnam War, also known as the Second Indochina War, began after France's withdraw from its colony Indochina. The region was split into four sovereign states: Cambodia, Laos, North Vietnam, and South Vietnam. While Cambodia and Laos became independent countries, North and South Vietnam became engulfed in a ruthless civil war. The war lasted for fifteen years. It began after the murder of Ngô Đình Diệm, the president of South Vietnam. He was overthrown by a South Vietnamese military coup d'etat. But after his assassination, which was backed by the United States, North Vietnam made their move, attacking two U.S. navel ships in the Tonkin Gulf. This lead President Lyndon B. Johnson to send military advisers and ground troops to support South Vietnam, without ever signing an official declaration of war from Congress.
After North Vietnam attacked an American airbase in Pleiku, President Johnson ordered the commencement of Operation: Rolling Thunder. The op was meant to bomb North Vietnam for their attack. Johnson also ordered the deployment of American ground forces, including marines and military advisers, to South Vietnam. The first battle was fought in Ia Drang Valley. America's use of helicopters kept them alive in the guerrilla warfare that North Vietnam used. North Vietnam took every opportunity to end the war for their side. The North secretly attacked South Vietnam on Tet, the Vietnamese New Year holiday. Before the North's attack, a treaty was signed, so the South and the Americans never expected to be attacked.
The end of the war
American continued to fight until 1973. By then, the citizens were tired of fighting a war, for what they believed was a lost cause. In the Paris Peace Agreement, America would withdrew its forces from South Vietnam, as long as North Vietnam recognized South Vietnam's government. The North agreed to the treaty, but this wasn't a peace agreement at all. It was secretly an American surrender. The treat never stated that the North had to withdraw its troops from the South. So, in 1975, when the last few Americans forces were still withdrawing from the country, the North attacked the South Vietnamese capital of Saigon. American helicopters, filled with American soldiers and South Vietnamese citizens, tried to escape the attack, but were shot down. This event marked the official end of the Vietnam War.