Cold War is the term used to describe the state of conflict, tension and competition that existed between the United States and the Soviet Union (USSR) and their respective allies from the mid-1940s to the early 1990s. Throughout this period, rivalry between the two superpowers was expressed through military coalitions, propaganda, espionage, weapons development, industrial advances, and competitive technological development, e.g., the space race. Both superpowers engaged in costly defense spending, a massive conventional and nuclear arms race, and numerous proxy wars. In the absence of a declared war between the US and the Soviet Union, the rival states participated in a half-century of military buildup and political battles for support around the world. These activities included the s...more >>ignificant involvement of allied and satellite nations in local "third party" wars. Although the US and the Soviet Union had been allied against the Axis powers, the two sides differed on how to reconstruct the postwar world even before the end of World War II. During the following decades, the Cold War spread beyond Europe to every region of the world, as the US sought the "containment" and "rollback" of communism and forged myriad alliances to this end, particularly in Western Europe and the Middle East. Meanwhile, the Soviet Union fostered Communist movements around the world, particularly in Eastern Europe, Latin America and Southeast Asia.