There are eleven metropolitan regions in Germany 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, only four cities in Germany surpass the threshold of at least one million inhabitants within their administrative borders: Berlin, Hamburg, Munich and Cologne.