The city has several progressive policies, such as abortion on request, a limited form of euthanasia, no-fault divorce, and same-sex marriage.
It is located in the Valley of Mexico (Valle de México), a large valley in the high plateaus in the center of Mexico, at an altitude of 2,240 meters (7,350 ft). The 2009 population for the city proper was approximately 8.84 million people, According to the most recent definition agreed upon by the federal and state governments, the population of Greater Mexico City is 21.3 million, which makes it the largest metropolitan area of the Western Hemisphere, the eleventh-largest agglomeration (2017), and the largest Spanish-speaking city in the world.
Mexico's capital is both the oldest capital city in the Americas and one of two founded by Native Americans, the other being Quito, Ecuador.
The city grew as the population did, coming up against the lake's waters.
As the depth of the lake water fluctuated, Mexico City was subject to periodic flooding.
Tensions increased until, on the night of June 30, 1520 – during a struggle known as "La Noche Triste" – the Aztecs rose up against the Spanish intrusion and managed to capture or drive out the Europeans and their Tlaxcalan allies.
He did not establish a territory under his own personal rule, but remained loyal to the Spanish crown.According to legend, the Mexicas' principal god, Huitzilopochtli, indicated the site where they were to build their home by presenting a golden eagle perched on a prickly pear devouring a rattlesnake.Between 13, Tenochtitlan grew in size and strength, eventually dominating the other city-states around Lake Texcoco and in the Valley of Mexico.A major labor draft, the desagüe, compelled thousands of Indians over the colonial period to work on infrastructure to prevent flooding.Floods were not only an inconvenience but also a health hazard, since during flood periods human waste polluted the city's streets.The causeways were rebuilt under Spanish rule with indigenous labor.