World War II: Capitulation of German garrison in Poznań. The city is liberated by Soviet and Polish forces.

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.

Poznań is a city on the River Warta in west Poland, within the Greater Poland region. The city is an important cultural and business center and one of Poland's most populous regions with many regional customs such as Saint John's Fair, traditional Saint Martin's croissants and a local dialect. Among its most important heritage sites are the Renaissance Old Town, Town Hall and Poznań Cathedral.

The Battle of Poznań during World War II in 1945 was an assault by the Soviet Union's Red Army that had as its objective the elimination of the Nazi German garrison in the stronghold city of Poznań (Posen) in occupied Poland. The defeat of the German garrison required a month-long reduction of fortified positions, urban combat, and a final assault on the city's citadel by the Red Army, complete with medieval touches.

The Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union, was a transcontinental country that spanned much of Eurasia from 1922 until it dissolved in 1991. During its existence, it was the largest country by area, extending across eleven time zones and sharing borders with twelve countries, and the third-most populous country. An overall successor to the Russian Empire, it was nominally organized as a federal union of national republics, the largest and most populous of which was the Russian SFSR. In practice, its government and economy were highly centralized. As a one-party state governed by the Communist Party of the Soviet Union (CPSU), it was the flagship communist state. Its capital and largest city was Moscow.