The Cold War was the strategic, economic and ideological struggle between the global superpowers the Soviet Union and the United States of America, supported by their respective and emerging alliance partners. Important allies of the United States were the United Kingdom, France, the Netherlands, Canada, Japan, South Korea, Saudi Arabia, West Germany, Australia and New Zealand. Important allies of the Soviet Union were East Germany, Poland, Czechoslovakia, Syria, Egypt (for a while), Romania, Cuba, North Korea, North Vietnam and while maintaining a tenuous relationship with a few other communist states like China and Yugoslavia. The Cold War lasted over four decades, from circa 1947 (the post-World War II period) until the collapse of the Soviet Union in 1991.
The struggle was widely called the Cold War because it did not involve direct armed conflict between the contestants. The Cold War was instead waged by means of diplomatic maneuvering, economic pressure, selective aid, intimidation, propaganda, assassination, low-intensity military operations and full-scale proxy war from circa 1947 until the terminal decline of the Warsaw Pact in the late 1980s. The Cold War also simultaneously witnessed the largest arms race in history, leading to widespread global fears of a potential nuclear war. In addition to the United States and the Soviet Union, the United Kingdom, France, China and Israel also possessed nuclear weapons during the Cold War. However the fear of causing a nuclear holocaust had prevented the nuclear powers to wage war against each other.