Current population: 19.8 million
The New York City metropolitan area was the world's first megacity and remains a 19.8 millionstrong powerhouse with global reach in everything from fashion to finance. It's been the most populated place in the U.S. since Census Bureau records began in 1790, and the city's five boroughs, spread over 301 sq. mi. (780 sq km), are also the most densely populated in America. New York City attracted nearly 50 million visitors in 2010 and is home to people from all corners of the globe (its residents speak an estimated 800 languages). It's also the second wealthiest city in the world, after Tokyo.
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