More people in history live in cities than ever before in our planets history.

Urbanization rates have increased dramatically in the last decade, according to a new report by the U.N. Settlements Program, UN-Habitat.

But the way people are urbanizing are changing. People aren't flocking to Europe and the United States as they did a century ago . A new class of cities is on the rise, and millions of people migrating to these new hubs throughout the developing world.

Business Insider analyzed the population growth from 1990 to the 2025 estimates for just under 600 of the world's most populous cities.