We have visitors from Mexico. What does Wikipedia tell about one of the largest cities in the world? It's one of the five most populated areas in the world.
Mexico City (Spanish: Ciudad de México, México D.F. or simply México, pronounced IPA: ['mexiko]) is the capital city of the nation of Mexico. The "Distrito Federal" is also commonly referred to as the "D.F." It is one of the largest cities in the world and is classed as a megalopolis as it encompasses one large city that has slowly engulfed other, smaller ones. It is located in the Valley of Mexico, a large valley in the high plateaus at the center of Mexico, about 2,240 meters (7,349 feet) above sea-level, surrounded on most sides by volcanoes towering at 4,000 to 5,500 meters (13,000 to 18,000 feet) above sea-level. Mexico City, as a municipality, was established in 1521 by Hernán Cortéz in the middle of the now drained Lake Texcoco on the ruins of Tenochtitlan, the capital of the Aztec Empire, and of its lesser-known twin city Tlatelolco. The municipality was abolished in 1928, and the name "Mexico City" can now refer to two things.
Officially, the name "Ciudad de México" is used by the Distrito Federal (D.F.). The D.F. is a federal district serving as the capital of Mexico and which is administered by the Mexican Federal Government. The D.F. encompasses the historical center of Mexico City, but is much larger than the historical municipality of Mexico City abolished in 1928. The urbanized area of Mexico City covers only the north of the D.F., while the south of the D.F. is made up of rural areas and mountains. Although the D.F. is not a municipality, the name "Ciudad de México" is used by Mexican authorities as a synonym for the Distrito Federal (Federal District).
According to the Constitution of Mexico, Mexico City is the Federal District, (Distrito Federal). This is actually a fairly recent reform (dating from 1993) of Article 44 of the Constitution, and it was aimed at ending two centuries of quite sterile discussions (and occasional problems on jurisdiction) about whether one concept engulfed the other or even if one of the two entities really had any legal existence in lieu of the other. The complete text of the aforementioned reform also states that Mexico City is the seat of the Powers of the Union (Executive, Legislative and Judicial) and capital of the United Mexican States.
In a broader meaning, "Mexico City" refers to the whole metropolitan area of Greater Mexico City. The metropolitan area extends beyond the limits of the D.F. and encompasses (as of 2000) 35 independent municipalities located in the State of México (Estado de México), to the north, east, and west of the D.F., extending as far north as the State of Hidalgo. The metropolitan area of Greater Mexico City had 17.8 million inhabitants at the 2000 Mexican census. This means Mexico City is among the five most populated metropolitan areas in the world on par with Tokyo, New York City, Seoul and São Paulo.
Mexico City, with its distinct mestizo culture, blending native Indian (Nahuatl) and Spanish heritages, has in recent decades become one of the great financial, economic, educational, cultural, and tourist centers of the world.