This is the map signed by Joseph Stalin and German Foreign Minister Joachim von Ribbentrop on August 23, 1939, when the USSR and Nazi Germany agreed to attack, conquer and divide Poland between themselves. It shows the planned border between Russian and German zones of occupation.
The attack started 4:45 am on September 1, 1939, on the German front – the Russians followed two weeks later, for logistical difficulties.
While the pact came as a rude shock to the world, it is widely unknown that it had been secretly prepared for many months by the Auswärtiges Amt, the German Foreign Office. While they wanted – after the war – to present the legend they had been only doing their job and were certainly not Nazis, their efforts are well documented and I have located them at Yale Law School. They will be the subject of a subsequent post.