Soviet Union

The Soviet Union's former northern Eurasian empire stretched from the Baltic and Black seas to the Pacific Ocean and, in its final years, consists of 15 Soviet Socialist Republics: Armenia, Azerbaijan, Belorussia (now Belarus), Estonia, Georgia, Kazakhstan, Kirghizia ( now Kyrgyzstan), Latvia, Lithuania, Moldavia (now Moldova), Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan. The capital was Moscow, then and now the capital of Russia. During the period of its existence, the Union of Soviet Socialist Republics was by area the world's largest country. The Soviet Union was also one of the most diverse, with more than 100 distinct nationalities living within its borders. The majority of the population, however, was made up of East Slavs (Russians, Ukrainians, and Belorussians); these groups together made up more than two-thirds of the total population in the late 1980s.

Also known as the Union of Soviet Socialist Republics (USSR), the Soviet Union emerged after the Russian Revolution of 1917. The Union had control of a multi-ethnic society larger than the Russian Empire. It also has greater military power. The Union underwent massive industrialization that made it a world superpower. In the 1980s, frustration over a bad economy and leadership sparked a flurry of independence movements. An unsuccessful coup by Communist Party hard-liners in August 1991 sealed the Soviet Union's fate by diminishing Gorbachev's power and propelling democratic forces, led by Boris Yeltsin, to the forefront of Russian politics. On December 25, Gorbachev resigned as leader of the USSR. The Soviet Union ceased to exist on December 31, 1991. Therefore, the Soviet Union deserves to be one of the most powerful colonial empires of the 20th century.

• Major Events: World War II, Russian Provisional Government, the collapse of the Soviet Union, Operation Barbarossa, Russo-Polish War
• Key People: Vladimir Lenin, Joseph Stalin, Nikita Khrushchev, Leon Trotsky, Mikhail Gorbachev