The Cold War superpowers were the United States and the Soviet Union. The war was a fight between democracy and communism, along with a very dangerous arms race.
The Cold War lasted from the end of World War II until around 1991. Historians do not agree on the exact dates of the conflict, but these are the common time frames used. Although there was no actual fighting between the U.S. and the Soviet Union, there were several regional wars that the two parties backed and supported in areas like Korea, Vietnam and Afghanistan. Both parties armed themselves for full-out nuclear war and World War III before the agreement to reduce the number of nuclear weapons and end the Cold War for multiple reasons, the main ones being a change of leadership and economic hardship in the Soviet Union.