The main cause of the Vietnam War was the spread of communism in Southeast Asia. The United States and its allies were determined to prevent the spread of communism, while North Vietnam and its allies were determined to unify Vietnam under communist rule.

North Vietnam was supported by China, the Soviet Union, and Cuba during the war. These countries provided North Vietnam with military and economic aid.

South Vietnam was supported by the United States, South Korea, and Thailand during the war. These countries provided South Vietnam with military and economic aid.

Operation Ranch Hand was the name of the American military operation that involved the use of napalm and Agent Orange. Napalm is a jellied gasoline that is used to create a firestorm, while Agent Orange is a herbicide that was used to defoliate forests and crops.

The Paris Peace Accords were signed in 1973 and ended the Vietnam War. The accords called for a cease-fire, the withdrawal of American troops from Vietnam, and the release of American prisoners of war.

58,220 American soldiers died in the Vietnam War.

Estimates of the number of Vietnamese soldiers who died in the Vietnam War range from 1 million to 2 million.

Estimates of the number of civilians who died in the Vietnam War range from 1 million to 2 million.

Richard Nixon was the American president who ordered the invasion of Cambodia in 1970.

Alexander Haig was the American general who led the invasion of Cambodia in 1970.

John McCain, James Stockdale, and Jeremiah Denton were all American helicopter pilots who were shot down and captured by the North Vietnamese.

John McCain, James Stockdale, and Jeremiah Denton were all held at the Hanoi Hilton, which was a POW camp in Hanoi, North Vietnam.

The Vietnam War Protest Movement, the Anti-Vietnam War Movement, and the Peace Movement were all American anti-war movements that protested the Vietnam War.

Blowin' in the Wind, For What It's Worth, and Where Have All the Flowers Gone? were all American songs that became anthems of the anti-war movement.

Apocalypse Now, Platoon, and Full Metal Jacket were all American movies that depicted the horrors of the Vietnam War.