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
Religion in Europe life. Christianity is still the largest religion in Europe. According to a 2010 study by the Pew Research Center, 76.2% of the European population identified themselves as Christians. According to a 2012 survey about Religiosity in the European Union in 2012 by Eurobarometer, Christianity was the largest religion in the European Union (account 72% of EU population), Catholics were the largest Christian group in EU, and accounted for 48% of the EU population, while Protestants made up 12%, Eastern Orthodox made up 8%, and other Christians 4%. There are numerous minor Protestant movements, including various Evangelical congregations. Islam came to