Mexico City is the capital of Mexico and seat of the federal powers of the Mexican Union. It is also the largest city in Mexico with a population of 8.84 million (2009) and the largest metropolitan area in the Americas with 21.2 million people.It is located in the Valley of Mexico, a large valley in the high plateaus at the center of Mexico, at an altitude of 2,240 metres (7,350 ft).

The city was originally built on an island of Lake Texcoco by the Aztecs in 1325 as Tenochtitlan. In 1524, the municipality of Mexico City was established and as of 1585 it was officially named La Ciudad de México (Mexico City). Mexico City served as the political, administrative and financial centre of a major part of the Spanish colonial empire. After independence from Spain was achieved, the Federal District was created in 1824.

Mexico City is the most important political, cultural, educational and financial center in the country. As an "alpha" global city Mexico City is one of the most important financial centers in North America. The Historic Centre and the "floating gardens" of Xochimilco in the southern borough have been declared World Heritage Sites by the UNESCO.