The USSR (Union of Soviet Socialist Republics) was formed after the Civil war of 1921 and became the World\’s first Marxist-Communist state in the world. After that it would become one of the biggest and most powerful nations in the world.The term Soviet Union and Russia are not one and the same, but they are closely related to each other. Both the terms are informally used the term, but actually Soviet Union was the term used instead of USSR (Union of Soviet Socialist Republics) whereas the term Russia was a statue in it. Russia is a part of the Soviet Union; people think that the Soviet Union is Russia because it was the largest country of the USSR.The Soviet Union was a union of 15 republican states. It existed from 1922 until its fall in 1991.\xa0