In cities of the developed world in-migration is another important factor causing city growth. In-migration refers to migration from former colonies and similar places. The fact that many immigrants settle in impoverished city centres led to the notion of the "peripherilazation of the core", which simply describes that people who used to be at the periphery of the former empires now live right in the centre.
Recent developments, such as inner-city redevelopment schemes, mean that new arrivals in cities no longer necessarily settle in the centre. It has been argued that this was never the norm, because settlement pattern differ a great deal between cities.