Mexico City Wikitravel
The greater Mexico City metropolitan area is one of the worlds 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