Germany invaded Poland on September 1, 1939, the Russians invaded 16 days later, thus beginning the European theatre of World War II. By October 6th the Germans and Russians occupied all of Poland. The war lasted for five years and eight months in Europe, and during that time Poland was home to some of the most notorious prison camps known to man; Auschwitz, Gross-Rosen, Stutthof. Overall there were roughly 250 camps in occupied Poland, both concentration and extermination. Over 3 million people were killed in those camps.