The biggest and everything else: the world’s top cities

Since we recently got to know the world’s tallest buildings, I think it’s high time (sorry) to discuss a few other urban superlatives. Let’s begin with people. Ranking the world’s cities by population is a tricky business. Strictly in terms of the census within city limits, Mumbai has the largest population of just under 13 million. But if you use the currently popular system of agglomerations favored by the United Nations, then the Tokyo-Yokohama-Kawasaki agglomeration is the world’s most populous city at 35 million people. But that’s not the only way to classify urban areas.

French geographer Jean Gottmann christened the area from Boston to Washington, DC as “Megalopolis” — or “BosWash” — and a case could be made that it acts as an urban continuum with an approximate population of 44 million. There are similarly hazy distinctions when figuring out which cities are largest in terms of area. For example, Juneau, AK is the largest city in the United States geographically, officially covering an absurd 3,081 square miles, making it larger than the state of Delaware; Jacksonville, FL is the largest city in the continental US, at 841 square miles. But if you buy into a demographic model of the New York City area, you’re looking at chunks of New Jersey and Connecticut as well — an area of 3,353 square miles. None can hold a candle to Hong Kong in terms of packing ‘em in, though. As the most population-dense city in the world, Hong Kong crams over 6 million people into 53 square miles (well over 100,000 people per square mile). Even for smaller cities, though, there are still ways to stake out a #1 spot. The Chinese city of Lijiang may be the only city higher than a mile above sea level with a population over 1 million. Potosi, Bolivia, and Cerro de Pasco, Peru, each claim to the world’s highest city, both set at about 2.5 miles above sea level. According to Guinness, the highest town in the world is the Tibetan hamlet of Wenzhuan, sitting pretty at over 3 miles up. Going from the heights to the depths, Moscow has the world’s most used subway system, serving over 3 billion passengers annually; the New York subway is the largest in size, covering 415 kilometers of track. Depth is harder to gauge, but the St. Petersburg Metro is generally considered the deepest system-wide, but Puhung Station on the Pyongyang Metro is thought to be the deepest subway station in the world at 100 meters down. But enough with sizes and directions … what about big, fat wallets? Opinions differ on that score as well. Some say Tokyo is the world’s most expensive city, while others pick London. And the Swiss maintain their national love of cash as Zurich takes top honors as the world’s richest city. Money isn’t everything, though — just ask Rio de Janeiro, confirmed by an overwhelming majority as the world’s sexiest city.