Soviet invasion of Poland World War II The 1939 Soviet invasion of Poland was a Soviet military operation that started without a formal declaration of war on 17 September 1939, during the early stages of World War II. Sixteen days after Nazi Germany invaded Poland from the west, the Soviet Union did so from the east. The invasion ended on 6 October 1939 with the division and annexing of the whole of the Second Polish Republic by Germany and the Soviet Union.
At 4.45 am on 1 September 1939 the German battleship Schleswig-Holstein opened fire on the Polish garrison of the Westerplatte Fort, Danzig (modern-day Gdansk), in what was to become the first military engagement of World War Two. Simultaneously, 62 German divisions supported by 1,300 aircraft commenced the invasion of Poland. The decision of Adolf Hitler to invade Poland was a gamble.
World War II: The Invasion of Poland and the Winter War
22 A young Polish boy returns to what was his home and squats among the ruins during a pause in the German air raids on Warsaw, Poland, in September of 1939. German attacks lasted until Warsaw surrendered on September 28. One week later, the last of the Polish forces capitulated near Lublin, giving full control of Poland to Germany and the Soviet Union. (AP Photo/Julien Bryan) World War II: The Invasion of Poland and the Winter War - In Focus - The Atlantic