The Holocaust in German-occupied Poland was the last stage of the Nazi "Final Solution of the Jewish Question" (Endlösung der Judenfrage) marked by the construction of death camps on Polish soil in 1941–42. The genocide officially sanctioned and executed by the Third Reich during World War II, collectively known as the Holocaust, took the lives of more than three million Polish Jews. The extermination camps played a central role in the implementation of the German policy of systematic and mostly successful destruction of over 90% of the indigenous Polish-Jewish population of the pre-war Second Polish Republic.