There are eleven metropolitan regions in Germany[1] consisting of the country's most densely populated cities and their catchment areas. They represent Germany's political, commercial and cultural centres. The eleven metropolitan regions in Germany were organised into political units for planning purposes.
Based on a narrower definition of metropolises commonly used to determine the metropolitan status of a given city,[2] only four cities in Germany surpass the threshold of at least one million inhabitants within their administrative borders: Berlin, Hamburg, Munich, and Cologne.
For urban centres outside metropolitan areas that are a similar focal point for their region, but on a smaller scale, the concept of the Regiopolis and the related concepts of regiopolitan area or regio were introduced by urban and regional planning professors in 2006.[3]
The five most important regions, collectively often called the Big Five,[4][5] are frequently compared with other European metropolitan regions (EMR) in terms of investment and market development.[6] They are (from north to south):
Hamburg, Berlin, the polycentric Ruhr-Düsseldorf-Cologne region (collectively referred to as Rhine-Ruhr), Frankfurt and Munich. The Globalization and World Cities Study Group (GaWC) considers Frankfurt and Munich as "α" (alpha) global cities, whereas the others are classified as "β" (beta) global cities.[7]
Each of them forms types of clusters and achieves varying levels of performance in areas, including business activity, human capital, information and technology exchange, cultural experience, and political engagement.[8]
^Prof. Dr. Iris Reuther (FG Stadt- und Regionalplanung, Universität Kassel): Presentation "Regiopole Rostock". 11 December 2008, retrieved 13 June 2009 (PDF).