During the Cold War from 1953 to 1979, Americans faced the possibility of enemy attack across the country, including Minnesota, as rivalry with the Soviet Union grew from earlier tensions after the Russian Civil War, uneasy alliance during World War II, and postwar conflict between communism and democracy and between socialism and capitalism. Devastating new weapons intensified the danger as the Soviets detonated an atomic bomb in 1949, tested a hydrogen bomb in 1953, created the impression of a large long-range bomber fleet in 1955, and launched Sputnik in 1957, while both superpowers escalated armaments under the tense policy of Mutually Assured Destruction. By the 1950s, the United States was installing missile defenses to protect major cities, industrial centers, and military bases from Soviet bombers, first deploying the Nike-Ajax in 1954 and then replacing it with the more powerful Nike-Hercules, installed near St. Bonifacius in 1958, which could carry atomic or conventional warheads. When Soviet priorities shifted from bombers to intercontinental ballistic missiles, the United States introduced the faster and more lethal Nike-Zeus, and the larger antiballistic missiles led to the end of Nike-Hercules facilities through Strategic Arms Limitation Talks agreements beginning in 1972; most of the nation’s 145 Nike-Hercules installations were deactivated by 1974, the remaining sites in Florida and Alaska closed five years later, and Nike-Hercules continued in Europe until the fall of Communism in Eastern Europe in the late 1980s.