The 15 Fastest-Growing Megacities

There are more than 25 "megacities" — that is, cities and their surrounding metropolitan areas with total populations of more than 10 million people — around the world. Including places such as New York, Tokyo and Rio de Janeiro, megacities are set for major growth over the next 10 years.

The New York metro area, for instance — which also includes Long Island, the Mid- and Lower Hudson Valley, the six largest cities in New Jersey, the six largest cities in Connecticut and five counties in northeastern Pennsylvania — is poised to reach 24 million people in 2025. That's a 20% increase from 2011. Read more...