Europe of population are Saint Petersburg, Madrid, Berlin and Rome, each having over 3 million residents. When considering the commuter belts or metropolitan areas, within the EU (for which comparable data is available) London covers the largest population, followed in order by Paris, Madrid, Barcelona, Berlin, the Ruhr area, Rome, Milan, Athens and Warsaw. "Europe" as a cultural concept is substantially derived from the shared heritage of the Roman Empire and its culture. The boundaries of Europe were historically understood as those of Christendom (or more specifically Latin Christendom), as established or defended throughout the medieval and early modern history of
Antisemitism in Europe invasion of Poland in 1939 and the beginning of World War II, the Nazis began the final solution of the Jews in Europe. The Jews were concentrated in ghettos and later sent to concentration and death camps where they were murdered. In the occupied territories of the USSR, Jews were murdered in mass numbers by death squads with the help of local population. This practice was later replaced by gassing the Jews in the death camps; the largest of them was Auschwitz. With the end of World War II in 1945, the surviving Jews began to return to their homes