What Is the World's Largest City?

The world's largest city by surface area is Hulunbuir, China, which is more than 100,000 square miles (about 250,000 square km) in area. To put it in perspective, that's bigger than 42 out of 50 American states. This is almost double the size of the next largest city of Jiuquan, also in China. The largest city outside of China is Altamira, Brazil, which is about 60,000 square miles (about 160,000 square km) in area.

More facts on super-sized cities:

The cities with the largest populations are Shanghai, Mumbai, Karachi, Delhi and Istanbul, all of which have populations of about 13 million people.

There are many contenders for the smallest city in the world, but most agree that it's either Hun, Croatia, with a population of 23; or Vatican City, which measures less than a fifth of a square mile (about a third of a square km).

The largest city in the U.S. by area is Yakutat City and Borough, Alaska, which is about 10,000 square miles (about 25,000 square km) in area. It is the eighth-largest city in the world by area. The largest U.S. city by population is New York, which has a population of about 8 million people.