The Cold War was an ideological war between the United States and the Soviet Union from 1945-1991. Each country tried to outdo the other by spreading their political and economic systems across the world through military alliances, arms build up, and proxy wars. Tensions escalated during events like the Berlin Blockade, Cuban Missile Crisis, and Vietnam War. The Cold War ended as Soviet leader Gorbachev instituted reforms allowing democratic elections, leading Eastern European countries to overthrow communist regimes and ultimately the dissolution of the Soviet Union.