Mexico City, Mexico, is one of the largest cities in the world. It was founded as the home of an ancient empire, was built on a lake and is now sinking. The federal district of Mexico City covers an area of 573 square miles.
The ancient empire that built Mexico City was the Aztecs, who began creating the city in 1325. It was built on a lake, Lago de Texcoco, a feat the Aztecs were able to achieve by creating an artificial island. The fact that it is on a lake has contributed to it sinking. Officials in Mexico City believe it is sinking at a rate of about 4 inches a year. This can be seen in many famous buildings, which have developed visible slopes.
Mexico City is regarded as one of the world's largest metropolises with a population of more than 20 million people. Only Tokyo, Japan, is bigger. It is also one of the richest cities in Latin America, with a gross domestic product per capita of $17,696. It is even home to one of the world's richest men, businessman Carlos Slim. As much as 15 percent of the city's population, however, lives in poverty.
Because of its huge population it suffers from air pollution. The city operates a system where cars with certain number plates can only drive on certain days.