1973 – Vietnam War: The last United States combat soldiers leave South Vietnam. The Vietnam War was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was a major conflict of the Cold War. While the war was officially fought between North Vietnam and South Vietnam, the north was supported by the Soviet Union, China, and other communist states, while the south was supported by the United States and other anti-communist allies, making the war a proxy war between the United States and the Soviet Union. It lasted almost 20 years, with direct U.S. military involvement ending in 1973. The conflict also spilled over into neighboring states, exacerbating the Laotian Civil War and the Cambodian Civil War, which ended with all three countries officially becoming communist states by 1976. The war exacted an enormous human cost: estimates of the number of Vietnamese soldiers and civilians killed range from 966,000 to 3 million. Some 275,000–310,000 Cambodians, 20,000–62,000 Laotians, and 58,220 U.S. service members also died in the conflict.