The dissolution of the Soviet Union (19881991) was the process of internal disintegration within the Soviet Union (USSR) which resulted in the end of the country's and the federal governments existence as a sovereign state, thereby resulting in its constituent republics gaining full sovereignty. It brought an end to General Secretary (later also President) Mikhail Gorbachev's effort to reform the Soviet political and economic system in an attempt to stop a period of political stalemate and economic backslide. The Soviet Union had experienced internal stagnation and ethnic separatism. The USSR, although a highly centralized state, was made up of 15 republics that served as homelands for different ethnicities. By late 1991, amidst a catastrophic political crisis, with several republics already departing the Union and centralized power waning, the leaders of three of its founding members declared that the Soviet Union no longer existed. Eight more republics joined their declaration shortly thereafter. Gorbachev resigned in December 1991 and what was left of the Soviet parliament voted to end itself. Along with the Revolutions of 1989 in the Eastern Bloc, the dissolution of the Soviet Union marked the end of the Cold War.

The process began with growing unrest in the Union's various constituent national republics developing into an incessant political and legislative conflict between them and the central government. Estonia was the first Soviet republic to declare state sovereignty inside the Union on November 16, 1988. Lithuania was the first republic to declare independence from the Soviet Union by the Act of March 11, 1990 with its Baltic neighbours and the Southern Caucasus republic of Georgia joining it in a course of two months.

In August 1991, communist hardliners and military elites tried to overthrow Gorbachev and stop the failing reforms in a coup, but failed. The turmoil led to the government in Moscow losing most of its influence, and many republics proclaiming independence in the following days and months. The secession of the Baltic states was recognized in September 1991. The Belovezh Accords were signed on December 8 by President Boris Yeltsin of Russia, President Kravchuk of Ukraine, and Chairman Shushkevich of Belarus, recognising each other's independence and creating the Commonwealth of Independent States (CIS) instead of the Soviet Union. Kazakhstan was the last nation to leave the Union, proclaiming independence on December 16. All the ex-Soviet republics, with the exception of Georgia and the Baltics, joined the CIS on December 21, signing the Alma-Ata Protocol. On December 25, Gorbachev resigned and turned over his presidential powersincluding control of the nuclear launch codesto Yeltsin, who was now the first president of the Russian Federation. That evening, the Soviet flag was lowered from the Kremlin and replaced with the Russian tricolour flag. The following day, the Supreme Soviet's upper chamber, the Soviet of the Republics formally dissolved the Union.In the aftermath of the Cold War, several of the former Soviet republics have retained close links with Russia and formed multilateral organizations such as CSTO, the CIS, the Eurasian Economic Community, the Union State, the Eurasian Customs Union, and the Eurasian Economic Union, for economic and military cooperation. On the other hand, the Baltic states and most of the former Warsaw Pact states became part of the European Union and joined NATO, while some of the other former Soviet republics like Ukraine, Georgia and Moldova have been publicly expressing interest in following the same path since the 1990s.

The Workers' and Peasants' Red Army, often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist Republic and, after 1922, the Union of Soviet Socialist Republics. The army was established in January 1918. The Bolsheviks raised an army to oppose the military confederations (especially the various groups collectively known as the White Army) of their adversaries during the Russian Civil War. Starting in February 1946, the Red Army, along with the Soviet Navy, embodied the main component of the Soviet Armed Forces; taking the official name of "Soviet Army", until its dissolution in 1991.

The Red Army provided the largest land force in the Allied victory in the European theatre of World War II, and its invasion of Manchuria assisted the unconditional surrender of Imperial Japan. During operations on the Eastern Front, it accounted for 75–80% of casualties the Wehrmacht and Waffen-SS suffered during the war and ultimately captured the Nazi German capital, Berlin.