The Cold War was a period of political tension and military rivalry between the United States and the Soviet Union that lasted from the late 1940s until the early 1990s. It was characterized by ideological conflict between capitalism and communism, leading to various proxy wars, arms races, and the formation of military alliances like NATO and the Warsaw Pact. During this time, both superpowers sought to expand their influence globally, often supporting opposing sides in conflicts around the world. Key events included the Cuban Missile Crisis, the Vietnam War, and the Berlin Wall's construction and fall, which symbolized the division between East and West.