If you live closer to sea level, you may experience difficulty breathing due to altitude and pollution.
Air quality has, however, been improved in the last few years.
During the Mexico-US war in 1847, the city was invaded by the American army.
In 1864 the French invaded Mexico and the emperor Ferdinand Maximilian of Hapsburg ruled the country from the Castillo de Chapultepec and ordered to build Avenue of the Empress (today's Paseo de la Reforma promenade).
Knowing what colonia you're going to is essential to getting around, almost all locals will know where a given colonia is (but note that there are some colonias with duplicate or very similar names).
As with many very large cities, the structure is relatively decentralized, with several parts of the city having their own miniature "downtown areas." However, the real downtown areas are Centro, the old city center, and Zona Rosa, the new business and entertainment district. Some people may have breathing difficulties at high altitudes and experience difficulty when breathing. This is far higher than any metropolitan area in the United States.
The 20th century saw the uncontrolled growth of the City beyond the Centro Historico with the influx of thousands of immigrants from the rest of the country.
In 1968, the city was host to the Olympic Games, which saw the construction of the Azteca Stadium, the Palacio de los Deportes, the Olympic Stadium and other sports facilities.
The city is officially divided into 16 delegaciones (boroughs) which are in turn subdivided into colonias (neighborhoods), of which there are over 1700; however, it is better to think of the city in terms of districts to facilitate the visitor getting around.
Many older towns like Coyoacán, San Angel and Tlalpan got merged into the urban sprawl, and each of these still manages to preserve some of their original and unique characteristics.
The greater Mexico City metropolitan area is one of the world's largest and the largest city by population in North America, with an estimated 26 million people living in the region.
It is shaped roughly like an oval of about 60 by 40km, built on the dry bed of Lake Texcoco, and surrounded on three sides by tall mountains and volcanoes such as the Ajusco, the Popocatepetl and the Ixtaccihuatl. Much in the same way that the city of Washington (urban pop.
Mexican weekends, in the sense of when it is common to go out drinking, are Thursday night to Sunday morning and sometimes throughout Sunday.