The Berlin Blockade (24 June 1948 12 May 1949) was one of the first major international crises of the Cold War. During the multinational occupation of postWorld War II Germany, the Soviet Union blocked the Western Allies' railway, road, and canal access to the sectors of Berlin under Western control. The Soviets offered to drop the blockade if the Western Allies withdrew the newly introduced Deutsche Mark from West Berlin.

The Western Allies organised the Berlin Airlift (German: Berliner Luftbrcke, lit.'"Berlin Air Bridge"') from 26 June 1948 to 30 September 1949 to carry supplies to the people of West Berlin, a difficult feat given the size of the city and the population. American and British air forces flew over Berlin more than 250,000 times, dropping necessities such as fuel and food, with the original plan being to lift 3,475 tons of supplies daily. By the spring of 1949, that number was often met twofold, with the peak daily delivery totalling 12,941 tons.Having initially concluded there was no way the airlift could work, the Soviets found its continued success an increasing embarrassment. On 12 May 1949, the USSR lifted the blockade of West Berlin, due to economic issues in East Berlin, although for a time the Americans and British continued to supply the city by air as they were worried that the Soviets would resume the blockade and were only trying to disrupt western supply lines. The Berlin Airlift officially ended on 30 September 1949 after fifteen months. The US Air Force had delivered 1,783,573 tons (76.40% of total) and the RAF 541,937 tons (23.30% of total), totalling 2,334,374 tons, nearly two-thirds of which was coal, on 278,228 flights to Berlin. In addition Canadian, Australian, New Zealand and South African air crews assisted the RAF during the blockade.:338 The French also supported but only to provide for their military garrison.American C-47 and C-54 transport airplanes, together, flew over 92,000,000 miles (148,000,000 km) in the process, almost the distance from Earth to the Sun. British transports, including Handley Page Haltons and Short Sunderlands, flew as well. At the height of the Airlift, one plane reached West Berlin every thirty seconds.Seventeen American and eight British aircraft crashed during the operation. A total of 101 fatalities were recorded as a result of the operation, including 40 Britons and 31 Americans, mostly due to non-flying accidents.

The Berlin Blockade served to highlight the competing ideological and economic visions for postwar Europe. It played a major role in aligning West Berlin with the United States as the major protecting power, and in drawing West Germany into the NATO orbit several years later in 1955.

The Soviet Union, officially the Union of Soviet Socialist Republics (USSR), was a communist state that spanned Eurasia from 1922 to 1991. It was nominally a federal union of multiple national republics; in practice its government and economy were highly centralized until its final years. The country was a one-party state (prior to 1990) governed by the Communist Party of the Soviet Union, with Moscow as its capital within its largest and most populous republic, the Russian SFSR. Other major urban centers were Leningrad (Russian SFSR), Kiev (Ukrainian SSR), Minsk (Byelorussian SSR), Tashkent (Uzbek SSR), Alma-Ata (Kazakh SSR) and Novosibirsk (Russian SFSR). It was the largest country in the world, covering over 22,402,200 square kilometres (8,649,500 sq mi), and spanning eleven time zones.

The Soviet Union had its roots in the October Revolution of 1917 when the Bolsheviks, headed by Vladimir Lenin, overthrew the Provisional Government that had earlier replaced the house of Romanov of the Russian Empire. They established the Russian Soviet Republic, the world's first constitutionally guaranteed socialist state. Tensions escalated into a civil war between the Bolshevik Red Army and many anti-Bolshevik forces across the former Empire, among whom the largest faction was the White Guard. The White Guard engaged in violent anti-communist repression against the Bolsheviks and suspected worker and peasant Bolsheviks known as the White Terror. The Red Army expanded and helped local Bolsheviks take power, establishing soviets, repressing their political opponents and rebellious peasants through Red Terror. By 1922, the balance of power had shifted and the Bolsheviks had emerged victorious, forming the Soviet Union with the unification of the Russian, Transcaucasian, Ukrainian and Byelorussian republics. Upon the conclusion of the civil war Lenin's government introduced the New Economic Policy, which led to a partial return of a free market and private property; this resulted in a period of economic recovery.

Following Lenin's death in 1924, Joseph Stalin came to power. Stalin suppressed all political opposition to his rule inside the Communist Party and inaugurated a command economy. As a result, the country underwent a period of rapid industrialization and forced collectivization, which led to significant economic growth, but also led to a man-made famine in 1932–1933. The Gulag labour camp system was also expanded in this period. Stalin also fomented political paranoia and conducted the Great Purge to remove his actual and perceived opponents from the Party through mass arrests of military leaders, Communist Party members, and ordinary citizens alike, who were then sent to correctional labor camps or sentenced to death.

On 23 August 1939, after unsuccessful efforts to form an anti-fascist alliance with Western powers, the Soviets signed a non-aggression pact with Nazi Germany. After the start of World War II, the formally neutral Soviets invaded and annexed territories of several Eastern European states, including the eastern regions of Poland, Lithuania, Latvia and Estonia. In June 1941 the Germans invaded, opening the largest and bloodiest theater of war in history. Soviet war casualties accounted for the majority of Allied casualties of the conflict in the process of acquiring the upper hand over Axis forces at intense battles such as Stalingrad. Soviet forces eventually captured Berlin and won World War II in Europe on 9 May 1945. The territory overtaken by the Red Army became satellite states of the Eastern Bloc. The Cold War emerged in 1947, where the Eastern Bloc confronted the Western Bloc, which would unite in the North Atlantic Treaty Organization in 1949.

Following Stalin's death in 1953, a period known as de-Stalinization and the Khrushchev Thaw occurred under the leadership of Nikita Khrushchev. The country developed rapidly, as millions of peasants were moved into industrialized cities. The USSR took an early lead in the Space Race with the first ever satellite and the first human spaceflight and the first probe to land on another planet, Venus. In the 1970s, there was a brief détente of relations with the United States, but tensions resumed when the Soviet Union deployed troops in Afghanistan in 1979. The war drained economic resources and was matched by an escalation of American military aid to Mujahideen fighters.

In the mid-1980s, the last Soviet leader, Mikhail Gorbachev, sought to further reform and liberalize the economy through his policies of glasnost and perestroika. The goal was to preserve the Communist Party while reversing economic stagnation. The Cold War ended during his tenure and in 1989, Warsaw Pact countries in Central and Eastern Europe overthrew their respective Marxist-Leninist regimes. Strong nationalist and separatist movements broke out across the USSR. Gorbachev initiated a referendum—boycotted by Lithuania, Latvia, Estonia, Armenia, Georgia, and Moldova — which resulted in the majority of participating citizens voting in favor of preserving the Union as a renewed federation. In August 1991, a coup d'état was attempted by Communist Party hardliners. It failed, with Russian President Boris Yeltsin playing a high-profile role in facing down the coup. The main result was the banning of the Communist Party. The republics, led by Russia and Ukraine, declared independence. On 25 December 1991, Gorbachev resigned. All the republics emerged from the dissolution of the Soviet Union as independent post-Soviet states. The Russian Federation (formerly the Russian SFSR) assumed the Soviet Union's rights and obligations and is recognized as its continued legal personality in world affairs.

The Soviet Union produced many significant social and technological achievements and innovations regarding military power. It boasted the world's second-largest economy and the largest standing military in the world. The USSR was recognized as one of the five nuclear weapons states. It was a founding permanent member of the United Nations Security Council as well as a member of the OSCE, the WFTU and the leading member of the Council for Mutual Economic Assistance and the Warsaw Pact.

Before its dissolution, the USSR had maintained its status as a superpower, alongside the United States, for four decades after World War II. Sometimes also called "Soviet Empire", it exercised its hegemony in East-Central Europe and worldwide with military and economic strength, proxy conflicts and influence in developing countries and funding of scientific research, especially in space technology and weaponry.