Soviet Union in the context of Maksutov telescope

World War II or the Second World War (1 September 1939 – 2 September 1945) was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were put on trial for war crimes.

The causes of World War II included unresolved tensions in the aftermath of World War I, the rise of fascism in Europe and militarism in Japan. Key events preceding the war included Japan's invasion of Manchuria in 1931, the Spanish Civil War, the outbreak of the Second Sino-Japanese War in 1937, and Germany's annexations of Austria and the Sudetenland. World War II is generally considered to have begun on 1 September 1939, when Nazi Germany, under Adolf Hitler, invaded Poland, after which the United Kingdom and France declared war on Germany. Poland was divided between Germany and the Soviet Union under the Molotov–Ribbentrop Pact. In 1940, the Soviet Union annexed the Baltic states and parts of Finland and Romania. After the fall of France in June 1940, the war continued mainly between Germany, now assisted by Fascist Italy, and the British Empire, with fighting in the Balkans, Mediterranean, and Middle East, the aerial Battle of Britain and the Blitz, and the naval Battle of the Atlantic. Through campaigns and treaties, Germany gained control of much of continental Europe and formed the Axis alliance with Italy, Japan, and other countries. In June 1941, Germany invaded the Soviet Union, opening the Eastern Front and initially making large territorial gains.

Enver Halil Hoxha (UK: /ˈhɒdʒə/ HOJ-ə, US: /ˈhɔːdʒɑː/ HAW-jah; Albanian: [ɛnˈvɛɾ ˈhɔdʒa] ; 16 October 1908 – 11 April 1985) was an Albanian communist revolutionary, statesman and political theorist who was the leader of Albania from 1944 until his death in 1985. He was the First Secretary of the Party of Labour of Albania from 1941 until his death, a member of its Politburo, chairman of the Democratic Front of Albania, and commander-in-chief of the Albanian People's Army. He was the twenty-second prime minister of Albania from 1944 to 1954 and at various times was both foreign minister and defence minister of the country.

Hoxha was born in Gjirokastër in 1908. After the Italian invasion of Albania, he joined the Party of Labour of Albania at its creation in 1941 in the Soviet Union. He was elected First Secretary in March 1943 at the age of 34. Less than two years after the liberation of the country, the monarchy of King Zog I was formally abolished, and Hoxha became the country's de facto head of state.

Romania is a country located at the crossroads of Central, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to the east, and the Black Sea to the southeast. It has a mainly continental climate, and an area of 238,397 km (92,046 sq mi) with a population of 19 million people. Romania is the twelfth-largest country in Europe and the sixth-most populous member state of the European Union. Europe's second-longest river, the Danube, empties into the Danube Delta in the southeast of the country. The Carpathian Mountains cross Romania from the north to the southwest and include Moldoveanu Peak, at an altitude of 2,544 m (8,346 ft). Bucharest is the country's capital, largest urban area, and financial centre. Other major urban areas include Cluj-Napoca, Timișoara, Iași, Constanța and Brașov.

Settlement in the territory of modern Romania began in the Lower Paleolithic, later becoming the Dacian Kingdom before Roman conquest and Romanisation. The modern Romanian state was formed in 1859 with the unification of Moldavia and Wallachia under Alexandru Ioan Cuza, becoming the Kingdom of Romania in 1881 under Carol I of Romania. Romania gained independence from the Ottoman Empire in 1877, formalised by the Treaty of Berlin. After World War I, Transylvania, Banat, Bukovina, and Bessarabia joined the Old Kingdom, forming Greater Romania, which reached its largest territorial extent. In 1940, under Axis pressure, Romania lost territories to Hungary, Bulgaria, and the Soviet Union. Following the 1944 Romanian coup d'état, Romania switched sides to join the Allies. After World War II, it regained Northern Transylvania through the Paris Peace Treaties. Under Soviet occupation, King Michael I was forced to abdicate, and Romania became a socialist republic and Warsaw Pact member. After the uniquely violent Romanian revolution in December 1989, Romania began a transition to liberal democracy and a market economy.

The 1994 Winter Olympics, officially known as the XVII Olympic Winter Games (Norwegian: De 17. olympiske vinterleker; Nynorsk: Dei 17. olympiske vinterleikane) and commonly known as Lillehammer '94, were an international winter multi-sport event held from 12 to 27 February 1994 in and around Lillehammer, Norway. Having lost the bid for the 1992 Winter Olympics to Albertville in France, Lillehammer was awarded the 1994 Winter Games on 15 September 1988, two days before the 1988 Summer Olympics opening ceremonies at the 94th IOC Session in Seoul, South Korea. Due to the calendar changes made in 1986, this was the only time that the Winter Olympics took place two years after the previous Winter Games, and the first to be held in a different year from the Summer Olympics. This meant that from now on, the Olympic Games are held on every even-numbered year instead of every four years. This was the first Winter Olympics that took place in a year with the Asian Games, Commonwealth Games, and FIFA World Cup. This was the second Olympic Games of any type hosted in Norway — the first being the 1952 Winter Olympics in Oslo — and the fourth Olympics overall to be held in a Nordic country, after the 1912 Summer Olympics in Stockholm, Sweden, and the 1952 Summer Olympics in Helsinki, Finland. Lillehammer is the northernmost city ever to host the Olympic Games.

Although Lillehammer Municipality was the main host, some events were held in neighboring municipalities, and the speed skating events were held in Hamar Municipality, some ice hockey matches were played in Gjøvik Municipality, and the Alpine skiing events were held in Øyer Municipality and Ringebu Municipality. Sixty-seven National Olympic Committees and 1,737 athletes participated in six sports and sixty-one events. Fourteen countries made their Olympic debuts, of which nine were former Soviet republics. The Games also saw the introduction of stricter and more rigid qualifying rules, reducing the number of under-performing participants. Six new events were introduced into the Olympic programme: new distances in short-track speed skating and aerials, and speed skating events were held indoors. Almost two million people spectated at the Games, which were the first to have the Olympic Truce in effect. The Olympics were followed by the 1994 Winter Paralympics from 10 to 19 March.

Batumi (/bɑːˈtuːmi/; Georgian: ბათუმი pronounced [ˈb̥a'tʰu.mi] ), historically Batum or Batoum, is the second-largest city of Georgia and the capital of the Autonomous Republic of Adjara. Located on the eastern shore of the Black Sea, about 20 kilometres (12 mi) north of the Georgia–Turkey border, Batumi lies at the foot of the Caucasus Mountains in a humid subtropical zone. As one of the country’s principal urban centers, it serves as a major seaport, commercial hub, and cultural gateway between Europe and Asia.

The city has played a significant role in the history of the south-eastern Black Sea region due to its deep-water harbor and strategic position along regional trade routes. Over the centuries, Batumi has been ruled by the Kingdom of Georgia, the Ottoman Empire, the Russian Empire, and the Soviet Union, each leaving distinct cultural and architectural imprints. Its economy historically relied on maritime trade and oil transit, particularly following the construction of the Baku–Batumi pipeline in the early 20th century. Today, it remains a key transit point for Caspian energy exports and regional commerce.

Russia, or the Russian Federation, is a country in Eastern Europe and North Asia. It is the largest country in the world, spanning eleven time zones and sharing land borders with fourteen countries. With a population of over 140 million, Russia is the most populous country in Europe and the ninth-most populous country in the world. It is a highly urbanised country, with sixteen of its urban areas having more than 1 million inhabitants. Moscow, the most populous metropolitan area in Europe, is the capital and largest city of Russia; and Saint Petersburg is its second-largest city and cultural centre.

Human settlement on the territory of modern Russia dates back to the Lower Paleolithic. The East Slavs emerged as a recognised group in Europe between the 3rd and 8th centuries AD. The first East Slavic state, Kievan Rus', arose in the 9th century, and in 988, it adopted Orthodox Christianity from the Byzantine Empire. Kievan Rus' ultimately disintegrated; the Grand Duchy of Moscow led the unification of Russian lands, leading to the proclamation of the Tsardom of Russia in 1547. By the early 18th century, Russia had vastly expanded through conquest, annexation, and the efforts of Russian explorers, developing into the Russian Empire, which remains the third-largest empire in history. However, with the Russian Revolution in 1917, Russia's monarchic rule was abolished and eventually replaced by the Russian SFSR—the world's first constitutionally socialist state. Following the Russian Civil War, the Russian SFSR established the Soviet Union with three other Soviet republics, within which it was the largest and principal constituent. The Soviet Union underwent rapid industrialisation in the 1930s, amidst the deaths of millions under Joseph Stalin's rule, and later played a decisive role for the Allies in World War II by leading large-scale efforts on the Eastern Front—rising as a global superpower. With the onset of the Cold War, it competed with the United States for ideological dominance and international influence. The Soviet era of the 20th century saw some of the most significant Russian technological achievements, including the first human-made satellite and the first human expedition into outer space.

The Dnieper or Dnepr (/(də)ˈniːpər/ (də-)NEE-pər), also called the Dnipro. is one of the major transboundary rivers of Europe, rising in the Valdai Hills near Smolensk, Russia, before flowing through Belarus and Ukraine to the Black Sea. Approximately 2,200 km (1,400 mi) long, with a drainage basin of 504,000 square kilometres (195,000 sq mi), it is the longest river of Ukraine and Belarus and the fourth-longest river in Europe, after the Volga, Danube, and Ural rivers.

In antiquity, the river was part of the Amber Road trade routes. During the Ruin in the later 17th century, the area was contested between the Polish–Lithuanian Commonwealth and the Russian Empire, dividing what is now Ukraine into areas described by its right and left banks. During the Soviet period, the river became noted for its major hydroelectric dams and large reservoirs. The 1986 Chernobyl disaster occurred on the Pripyat River, a tributary of the Dnieper, just upstream from its confluence with the Dnieper. The Dnieper is an important navigable waterway for the economy of Ukraine and is connected by the Dnieper–Bug Canal to other waterways in Europe. During the 2022 Russian invasion of Ukraine, certain segments of the river were made part of the defensive lines between territory controlled by the Russians and the Ukrainians.

Eastern Europe is a subregion of the European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural and socio-economic connotations. Its eastern boundary is marked by the Ural Mountains, and its western boundary is defined in various ways. Narrow definitions, in which Central and Southeast Europe are counted as separate regions, include Belarus, Russia and Ukraine. In contrast, broader definitions include Moldova and Romania, but also some or all of the Balkans, the Baltic states, the Caucasus, and the Visegrád group. In Eastern Europe, Russia is the largest and most populous country.

The region represents a significant part of European culture; the main socio-cultural characteristics of Eastern Europe have historically largely been defined by the traditions of the Slavs, as well as by the influence of Eastern Christianity as it developed through the Eastern Roman Empire and the Ottoman Empire. Another definition was created by the Cold War, as Europe was ideologically divided by the Iron Curtain, with "Eastern Europe" being synonymous with communist states constituting the Eastern Bloc under the influence of the Soviet Union.

The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States also asserts sovereignty over five major island territories and various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's third-largest land area and third-largest population, exceeding 340 million.

Paleo-Indians first migrated from North Asia to North America over 12,000 years ago, and formed various civilizations. Spanish colonization established Spanish Florida in 1513, the first European colony in what is now the continental United States. British colonization followed with the 1607 settlement of Virginia, the first of the Thirteen Colonies. Enslavement of Africans was practiced in all colonies by 1770 and supplied most of the labor for the Southern Colonies' plantation economy. Clashes with the British Crown over taxation and lack of parliamentary representation sparked the American Revolution, leading to the Declaration of Independence on July 4, 1776. Victory in the 1775–1783 Revolutionary War brought international recognition of U.S. sovereignty and fueled westward expansion, dispossessing native inhabitants. As more states were admitted, a North–South division over slavery led the Confederate States of America to attempt secession and fight the Union in the 1861–1865 American Civil War. With the United States' victory and reunification, slavery was abolished nationally. By 1900, the country had established itself as a great power, a status solidified after its involvement in World War I. Following Japan's attack on Pearl Harbor in 1941, the U.S. entered World War II. Its aftermath left the U.S. and the Soviet Union as rival superpowers, competing for ideological dominance and international influence during the Cold War. The Soviet Union's collapse in 1991 ended the Cold War, leaving the U.S. as the world's sole superpower.

Foreign policy, also known as external policy, is the set of strategies and actions a state employs in its interactions with other states, unions, and international entities. It encompasses a wide range of objectives, including defense and security, economic benefits, and humanitarian assistance. The formulation of foreign policy is influenced by various factors such as domestic considerations, the behavior of other states, and geopolitical strategies. Historically, the practice of foreign policy has evolved from managing short-term crises to addressing long-term international relations, with diplomatic corps playing a crucial role in its development.

The objectives of foreign policy are diverse and interconnected, contributing to a comprehensive approach for each state. Defense and security are often primary goals, with states forming military alliances and employing soft power to combat threats. Economic interests, including trade agreements and foreign aid, are central to a country's role in the global economy. Additionally, many states have developed humanitarian programs based on the responsibility to protect, supporting less powerful countries through various forms of assistance. The study of foreign policy examines the reasons and methods behind state interactions, with think tanks and academic institutions providing research and analysis to inform policy decisions.

Moldova, officially the Republic of Moldova, is a landlocked country in Eastern Europe, with an area of 33,843 km (13,067 sq mi) and a population of 2.38 million. Moldova is bordered by Romania to the west and Ukraine to the north, east, and south. The unrecognised breakaway state of Transnistria lies across the Dniester river on the country's eastern border with Ukraine. Moldova is a unitary parliamentary representative democratic republic with its capital in Chișinău, the country's largest city and main cultural and commercial centre.

Most of Moldovan territory was a part of the Principality of Moldavia from the 14th century until 1812, when it was ceded to the Russian Empire by the Ottoman Empire (to which Moldavia was a vassal state) and became known as Bessarabia. In 1856, southern Bessarabia was returned to Moldavia, which three years later united with Wallachia to form Romania. Still, Russian rule was restored over the entire region in 1878. During the 1917 Russian Revolution, Bessarabia briefly became an autonomous state within the Russian Republic. In February 1918, it declared independence and then integrated into Romania later that year following a vote of its assembly. The decision was disputed by Soviet Russia, which in 1924 established, within the Ukrainian SSR, a so-called Moldavian autonomous republic on partially Moldovan-inhabited territories to the east of Bessarabia. In 1940, as a consequence of the Molotov–Ribbentrop Pact, Romania was compelled to cede Bessarabia and Northern Bukovina to the Soviet Union, leading to the creation of the Moldavian Soviet Socialist Republic (Moldavian SSR).

Albert Camus (/kæˈmuː/ ka-MOO; French: [albɛʁ kamy] ; 7 November 1913 – 4 January 1960) was a French philosopher, novelist, author, dramatist, journalist, world federalist, and political activist. He was the recipient of the 1957 Nobel Prize in Literature at the age of 44, the second-youngest recipient in history. His works include The Stranger, The Plague, The Myth of Sisyphus, The Fall and The Rebel.

Camus was born in French Algeria to pied-noir parents. He spent his childhood in a poor neighbourhood and later studied philosophy at the University of Algiers. He was in Paris when the Germans invaded France during World War II in 1940. Camus tried to flee but finally joined the French Resistance where he served as editor-in-chief at Combat, an outlawed newspaper. After the war, he was a celebrity figure and gave many lectures around the world. He married twice but had many extramarital affairs. Camus was politically active; he was part of the left that opposed Joseph Stalin and the Soviet Union because of their totalitarianism. Camus was a moralist and leaned towards anarcho-syndicalism. He was part of many organisations seeking European integration. During the Algerian War (1954–1962), he kept a neutral stance, advocating a multicultural and pluralistic Algeria, a position that was rejected by most parties.

Capital punishment, also known as the death penalty and formerly called judicial homicide, is the state-sanctioned killing of a person as punishment for actual or supposed misconduct. The sentence ordering that an offender be punished in such a manner is called a death sentence, and the act of carrying out the sentence is an execution. A prisoner who has been sentenced to death and awaits execution is condemned and is commonly referred to as being "on death row". Etymologically, the term capital (lit. 'of the head', derived via the Latin capitalis from caput, "head") refers to execution by beheading, but executions are carried out by many methods.

Crimes that are punishable by death are known as capital crimes, capital offences, or capital felonies, and vary depending on the jurisdiction, but commonly include serious crimes against a person, such as murder, assassination, mass murder, child murder, aggravated rape, terrorism, aircraft hijacking, war crimes, crimes against humanity, and genocide, along with crimes against the state such as attempting to overthrow government, treason, espionage, sedition, and piracy. Also, in some cases, acts of recidivism, aggravated robbery, and kidnapping, in addition to drug trafficking, drug dealing, and drug possession, are capital crimes or enhancements. However, states have also imposed punitive executions, for an expansive range of conduct, for political or religious beliefs and practices, for a status beyond one's control, or without employing any significant due process procedures. Judicial murder is the intentional and premeditated killing of an innocent person by means of capital punishment. For example, the executions following the show trials in the Soviet Union during the Great Purge of 1936–1938 were an instrument of political repression.

Nazi Germany, officially the German Reich and later the Greater German Reich, was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a totalitarian dictatorship. The Third Reich, meaning "Third Realm" or "Third Empire", referred to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which the Nazis referred to as the Thousand-Year Reich, ended in May 1945, after 12 years, when the Allies defeated Germany and entered the capital, Berlin, ending World War II in Europe.

After Hitler was appointed Chancellor of Germany in 1933, the Nazi Party began to eliminate political opposition and consolidate power. A 1934 German referendum confirmed Hitler as sole Führer (leader). Power was centralised in Hitler's person, and his word became the highest law. The government was not a co-ordinated, cooperating body, but rather a collection of factions struggling to amass power. To address the Great Depression, the Nazis used heavy military spending, extensive public works projects, including the Autobahnen (motorways) and a massive secret rearmament program, forming the Wehrmacht (armed forces), all financed by deficit spending. The return to economic stability and end of mass unemployment boosted the regime's popularity. Hitler made increasingly aggressive territorial demands, seizing Austria in the Anschluss of 1938, and the Sudetenland region of Czechoslovakia. Germany signed a non-aggression pact with the Soviet Union and invaded Poland in 1939, launching World War II in Europe. In alliance with Fascist Italy and other Axis powers, Germany conquered most of Europe by 1940 and threatened Britain.

Several different governments controlled the Crimean Peninsula during the period of the Soviet Union, from the 1920s to 1991. The government of Crimea from 1921 to 1936 was the Crimean Autonomous Socialist Soviet Republic, which was an Autonomous Soviet Socialist Republic within the Russian Soviet Federative Socialist Republic (SFSR); the name was altered slightly to the Crimean Autonomous Soviet Socialist Republic from 1936 to 1945.

The Russian Soviet Federative Socialist Republic (Russian SFSR), previously known as the Russian Socialist Federative Soviet Republic (RSFSR) and the Russian Soviet Republic, and unofficially as Soviet Russia, was a socialist state from 1917 to 1922, and afterwards the largest and most populous constituent republic of the Soviet Union (USSR) from 1922 to 1991, until becoming a sovereign part of the Soviet Union with priority of Russian laws over Union-level legislation in 1990 and 1991, the last two years of the existence of the USSR. The Russian SFSR was composed of sixteen smaller constituent units of autonomous republics, five autonomous oblasts, ten autonomous okrugs, six krais and forty oblasts. Russians formed the largest ethnic group. The capital of the Russian SFSR and the USSR as a whole was Moscow and the other major urban centers included Leningrad (Petrograd until 1924), Stalingrad (Volgograd after 1961), Novosibirsk, Sverdlovsk, Gorky and Kuybyshev.

On 7 November 1917 [O.S. 25 October], as a result of the October Revolution, the Russian Soviet Republic was proclaimed as a sovereign state and the world's first constitutionally socialist state guided by communist ideology. The first constitution was adopted in 1918. In 1922, the Russian SFSR signed a treaty officially creating the USSR. On 12 June 1990, the Congress of People's Deputies adopted the Declaration of State Sovereignty. On 12 June 1991, Boris Yeltsin, supported by the Democratic Russia pro-reform movement, was elected the first and only President of the RSFSR, a post that would later become the Presidency of the Russian Federation. The August 1991 Soviet coup d'état attempt in Moscow with the temporary brief internment of President Mikhail Gorbachev destabilised the Soviet Union. Following these events, Gorbachev lost all his remaining power, with Yeltsin superseding him as the pre-eminent figure in the country. On 8 December 1991, the heads of Russia, Ukraine and Belarus signed the Belovezha Accords declaring dissolution of the USSR and established the Commonwealth of Independent States (CIS) as a loose replacement confederation. On 12 December, the agreement was ratified by the Supreme Soviet (the parliament of the Russian SFSR); therefore the Russian SFSR had renounced the Treaty on the Creation of the USSR and de facto declared Russia's independence from the USSR itself and the ties with the other Soviet republics.

The deportation of the Crimean Tatars (Crimean Tatar: Qırımtatar halqınıñ sürgünligi, Cyrillic: Къырымтатар халкъынынъ сюргюнлиги) or the Sürgünlik ('exile') was the ethnic cleansing and the cultural genocide of at least 191,044 Crimean Tatars that was carried out by Soviet Union authorities from 18 to 20 May 1944, supervised by Lavrentiy Beria, chief of Soviet state security and the secret police, and ordered by the Soviet leader Joseph Stalin. Within those three days, the NKVD used cattle trains to deport the Crimean Tatars, even Soviet Communist Party members and Red Army soldiers, from Crimea to the Uzbek SSR, several thousand kilometres away. They were one of several ethnicities that were subjected to Stalin's policy of population transfer in the Soviet Union.

Officially, the Soviet government presented the deportation as a policy of collective punishment, based on its claim that some Crimean Tatars collaborated with Nazi Germany in World War II, despite the fact that the 20,000 who collaborated with the Axis powers were half the 40,000 who served in the Soviet Red Army. Several modern scholars believe rather that the government deported them as a part of its plan to gain access to the Dardanelles and acquire territory in Turkey, where the Turkic ethnic kin of the Tatars lived, or remove minorities from the Soviet Union's border regions. By the end of the deportation, not a single Crimean Tatar lived in Crimea, and 80,000 houses and 360,000 acres of land were left abandoned. Nearly 8,000 Crimean Tatars died during the deportation, and tens of thousands subsequently perished due to the harsh living conditions in which they were forced to live during their exile. After the deportation, the Soviet government launched an intense detatarization campaign in an attempt to erase the remaining traces of Crimean Tatar existence.

Joseph Vissarionovich Stalin (né Dzhugashvili; 18 December [O.S. 6 December] 1878 – 5 March 1953) was a Soviet politician, dictator and revolutionary who led the Soviet Union from 1924 until his death in 1953. His rule oversaw mass atrocities that caused an estimated 20 million deaths, and he is widely considered one of the most brutal despots of the modern era. He held office as General Secretary of the Communist Party from 1922 to 1952 and as premier from 1941 until his death. Despite initially governing the country as part of a collective leadership, he eventually consolidated power to become a dictator by the 1930s. Stalin codified the party's official interpretation of Marxism as Marxism–Leninism, and his version of it is referred to as Stalinism.

Born into a poor Georgian family in Gori, Russian Empire, Stalin attended the Tiflis Theological Seminary before joining the Marxist Russian Social Democratic Labour Party. He raised funds for Vladimir Lenin's Bolshevik faction through bank robberies and other crimes, and edited the party's newspaper, Pravda. He was repeatedly arrested and underwent several exiles to Siberia. After the Bolsheviks seized power in the October Revolution of 1917, Stalin served as a member of the Politburo, and from 1922 used his position as General Secretary to gain control over the party bureaucracy. After Lenin's death in 1924, Stalin won the leadership struggle over rivals including Leon Trotsky. Stalin's doctrine of socialism in one country became central to the party's ideology, and his five-year plans starting in 1928 led to forced agricultural collectivisation, rapid industrialisation, and a centralised command economy. His policies contributed to a famine in 1932–1933 which killed millions, including in the Holodomor in Ukraine. Between 1936 and 1938, Stalin executed hundreds of thousands of his real and perceived political opponents in the Great Purge. Under his regime, an estimated 18 million people passed through the Gulag system of forced labour camps, and more than six million people, including kulaks and entire ethnic groups, were deported to remote areas of the country.

In 1954, the Presidium of the Supreme Soviet of the Soviet Union transferred the Crimean Oblast from the Russian SFSR to the Ukrainian SSR. The territory had been recognized within the Soviet Union as having "close ties" to the Ukrainian SSR, and the transfer commemorated the Union of Russia and Ukraine Tercentenary.

Amidst the dissolution of the Soviet Union in 1991, the Ukrainian SSR seceded from the Soviet Union and Ukraine continued to exercise sovereignty over the territory as the Autonomous Republic of Crimea. Russia did not dispute the Ukrainian administration of Crimea for just over two decades, but retracted this stance on 18 March 2014, when Crimea was annexed by Russia after coming under Russian military occupation.