Soviet Invasion of Poland 1939: Stalin, Hitler, and the Partition of Poland

The Soviet invasion of Poland on 17 September 1939 completed the partition of Poland and reshaped Eastern Europe at the start of World War II. On 1 September 1939, Nazi Germany invaded Poland, marking the beginning of World War II. Just over two weeks later, the Soviet Union attacked from the east—sealing Poland’s fate. This video explores the Molotov–Ribbentrop Pact, the secret deal between Adolf Hitler and Joseph Stalin that divided Eastern Europe into spheres of influence and led directly to the partition of Poland. It also examines cooperation between the NKVD — the Soviet Union’s internal security and secret police responsible for political repression, arrests, and deportations — and the Gestapo — Nazi Germany’s secret state police tasked with eliminating opposition through surveillance, imprisonment, and terror. Together, they played a key role in crushing Polish resistance and dismantling the Polish state. Discover why the Soviets chose to invade, how strategic fears and territorial ambitions shaped their decision, and how, despite occupation and repression, Poland’s underground resistance continued the fight for independence.This episode is part of the series Battles & Operations of World War II.Watch the full documentary and explore hundreds of historical films at:WorldHistory.tv