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 (194,000) which is home to Eastern Europe's largest Jewish community. During the Enlightenment, Deism became influential especially in France, Germany, the Netherlands, and the United Kingdom. Biblical concepts were challenged by concepts such as a heliocentric universe and other scientific challenges to the Bible. Notable early deists include Voltaire and Kant . The trend towards secularism during the 20th and 21st centuries has a number of reasons, depending on the individual country: The trend towards secularism has been less pronounced in the traditionally Catholic countries of Mediterranean Europe. Greece as the only traditionally Eastern Orthodox country in Europe which has