The Cold War was a period of geopolitical tension between the United States and Soviet Union from 1945 to 1991. Reasons for the Cold War included differing political ideologies between capitalism and communism, as well as distrust between the two superpowers following World War II. During the Cold War, the US and USSR engaged in proxy wars, arms races, space races, propaganda campaigns, and espionage as each sought to contain the influence and military strength of the other. The Cold War ended in the late 1980s and early 1990s with the fall of communism in Eastern Europe and dissolution of the Soviet Union.