The document discusses the rise of tensions between the Soviet Union and Western allies like the United States following World War II, leading to the Cold War era. It describes how the Soviet Union exerted control over Eastern Europe by installing communist governments and suppressing opposition. The West responded through policies like the Truman Doctrine and Marshall Plan to contain Soviet expansion and rebuild Western Europe. It also discusses the Berlin Blockade crisis of 1948-1949 and the formation of NATO in response to Soviet actions.