9. Shenzhen, China

What was a tiny fishing village on the border of Hong Kong in 1970 is now a buzzing metropolis of over four million people. With 13 buildings at over 200 meters tall, including the Shun Hing Square (the 8th tallest building in the world), Shenzen is a marvel of lights after sunset. You can't help but ask yourself if you are in a video game or in a real city.

Metro/Urban Population: 4.2 million