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
Population ageing increasingly higher levels of annual net migration will be required to maintain a target of even zero population growth". The worlds older population is growing dramatically. Asia and Europe are the two regions where a significant number of countries face population ageing in the near future. Within twenty years many countries in these regions will face a situation where the largest population cohort will be those over 65 and average age approach 50 years old. The Oxford Institute of Population Ageing is an institution looking at global population ageing. Its research reveals that many of the views of global ageing