&gt; Whether those regions will eventually grow into megacities or merely &quot;polycentric urban areas&quot; (as Wikipedia describes the Ruhr region) is ultimately philosophical.<p>I think defining regions around cities vs. regions around an area (Franken, Ostfriesland, etc.) makes some difference. In one concept the big city is the central point of orientation&#x2F;development&#x2F;... It&#x27;s not necessarily political the center, but where the money, the development, the modernity and the culture is located. The other concept of the &#x27;region&#x27; distributes power&#x2F;wealth&#x2F;culture&#x2F;infrastructure across the region more even, with some respect for the different strengths of the enclosed areas.