Cold War refers to the post-World War II struggle and competition between the United States and its allies and the Soviet Union and its allies. From mid-1940s to late 1980s, international politics was heavily influenced by intense rivalry between the two powerful groups of nations, accompanied by military coalitions, weapons development, space race, invasions, espionage and propaganda. It also divided the world along two political ideologies - democracy and capitalism promoted by the U.S., and communism propagated by the Soviet Union. The cold war ended with the collapse of Soviet Union in 1991.