The Cold War between the United States and the Soviet Union lasted for decades and led the two superpowers to the brink of nuclear disaster. The term “cold war” defines decades of mutual distrust and hostility that never developed into open warfare. The end World War II began a deadly arms race. In 1949, the Soviets tested an atom bomb of their own. In response, President Truman announced that the United States would build an even more destructive atomic weapon: the hydrogen bomb, or “superbomb.” Russian leader Joseph Stalin followed suit. As this anticommunist hysteria spread throughout the 1950s, Hollywood writers, directors, actors and others were unable to work; liberal college professors lost their jobs, people were asked to testify against colleagues and “loyalty oaths” became commonplace, this was referred to as McCarthyism. The ever-present threat of nuclear annihilation had a great impact on American domestic life as well. People built bomb shelters in their backyards. They practiced air raid attack drills in schools and other public places. The 1950's and 1960's spawned an epidemic of popular films that horrified moviegoers with depictions of nuclear devastation and mutant creatures. The late 1950's saw the advent of the Space Race and President John F. Kennedy made the bold public claim that the U.S. would land a man on the moon by the end of the decade. U.S. astronauts came to be seen as the ultimate American heroes. Soviets, in turn, were pictured as the ultimate villains, with their massive, relentless efforts to surpass America and prove the power of the communist system.