On this day, September 17, 1939, Stalin, following the agreement signed with Adolf Hitler the previous month, invaded Poland exactly 17 days after the Nazi invasion began. According to the agreement signed between the Nazis and Communists, Poland would be split in half, with Stalin annexing the eastern part of the country.

In this video, we can see Nazi and Communist officers and soldiers shaking hands and fraternizing during the joint Nazi-Soviet invasion of Poland.