World War II: A joint German–Soviet military parade in Brest-Litovsk is held to celebrate the successful invasion of Poland.

World War II or the Second World War 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 tried for war crimes.

The German–Soviet military parade in Brest-Litovsk was an official ceremony held by the troops of Nazi Germany and the Soviet Union on September 22, 1939, during the invasion of Poland in the city of Brest-Litovsk. It marked the withdrawal of German troops to the demarcation line secretly agreed to in the Molotov–Ribbentrop Pact, and the handover of the city and its fortress to the Soviet Red Army.