The Cold War was a period of political and military tension between Western powers led by the United States and Eastern powers led by the Soviet Union from 1947 to 1991. It began after World War II as the Soviet Union sought to expand its influence by supporting communist governments. This led to conflicts like the Korean War from 1950 to 1953, where North Korea invaded South Korea and both the US and USSR backed opposing sides, resulting in a stalemate. Throughout the Cold War, both superpowers engaged in an arms race, stockpiling nuclear weapons, and had confrontations like the Cuban Missile Crisis in 1962, where the US blocked the USSR from placing missiles in Cuba.