“The mega-city — usually defined as a city with a population of 10 million or more — isn’t a new phenomenon, or one that China invented. Yet urbanists are looking to China (where Shanghai and Beijing are already mega-cities, and at least a dozen others are huge, if not “mega”) to find the capital of the 21st century, rather like Paris was the capital of the 19th, and New York the capital of the 20th.”