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]