The Cold War was a long period of tension between the democracies of the Western World and the communist countries, including the Soviet Union. The west was led by the United States, and Eastern Europe was led by the Soviet Union. These two countries took the title of "superpowers." Although the two countries never officially declared war on each other, they fought indirectly, through proxy wars, arms race, and space race.
Rivalry between the United States and the Soviet Union for control over the postwar world emerged before World War II had even ended. U.S. presidents Franklin D. Roosevelt and Harry S Truman and Soviet leader Joseph Stalin never really trusted one another, even while working together to defeat the Nazis. Stalin resented the fact that the United States and Great Britain had not shared nuclear weapons research with the Soviet Union during the war and was unhappy with the countries’ initial unwillingness to engage the Germans on a second front in order to take pressure off of the Soviets. Additionally, Stalin was disproved by the fact that Truman had offered relief loans to Great Britain but not to the USSR.
