The Cold War (1945-1991) represented a series of localized conflicts and intense diplomatic rivalries between camps led by the capitalist United States and Communist Soviet Union. This era also saw a massive increase in civilian and military technology, including thousands of nuclear weapons and the means to deliver them across the planet.
This era was largely an outgrowth of the previous decades, with a special focus on the roles the United States and Soviet Union played in the Second World War. As Europe and Asia prepared for a long rebuilding process both sides offered their own visions for a postwar reality and security.
The Soviet Union under dictator Josef Stalin had several overarching goals and fears in the waning days of the Second World War. Stalin kept in mind the devastation that Russia faced in successive crises including the First World War and Russian Civil War. Stalin had particular distrust for the Western Allies due to intervention by these powers against the Reds in the Russian Civil War and for abandoning Czechoslovakia before the war began. These are among the factors that pushed Stalin into signing a non-aggression pact with Nazi Germany in 1941. Now facing betrayal by Hitler, massive destruction, and about 20 million military and civilian deaths, the Soviet Union was in a unique position. Soviet Red Army troops now occupied almost half of Europe and was the largest military force in the world. 
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