civilizations of what now is known as Mexico
are usually divided in two regions: Mesoamerica,
in reference to the cultural area in which several complex civilizations
developed before the arrival of the Spanish in the sixteenth century,
and Aridoamerica (or simply "The North") in reference to the
arid region north of the Tropic of Cancer in which few civilizations developed
and was mostly inhabited by nomadic or semi-nomadic groups.
was densely populated by diverse indigenous ethnic groups which, although
sharing common cultural characteristics, spoke different languages and
developed unique civilizations.
One of the most influential civilizations that developed in Mesoamerica was the Olmec civilization, sometimes referred to as the "Mother Culture of Mesomaerica". The later civilization in Teotihuacán reached its peak around 600 AD, when the city became the sixth largest city in the world, whose cultural and theological systems influenced the Toltec and Aztec civilizations in later centuries. Evidence has been found on the existence of multiracial communities or neighborhoods in Teotihuacan (and other large urban areas like Tenochtitlan). The Maya civilization, though also influenced by other Mesoamerican civilizations, developed a vast cultural region in south-east Mexico and northern Central America, while the Zapotec and Mixtec culture dominated the valley of Oaxaca, and the Purepecha in western Mexico.
The most significant groups are the Tarahumaras, Nahuas, Huicholes, Purépechas, Mixtecos, Zapotecas, Otomís, Totonacas and Mayas. They still form the major population group in some regions of the country, but as in other parts of the world, indigenous peoples in Mexico are treated as worth-less, second class citizens by 'pure European' Mexicans and mixed race mestizos (like Travellers in Ireland). High levels of migration to the cities - where they often end up as the cheapest of the cheap labour - and to the U.S. has been one consequence of the loss of traditional lands.
There are 62 indigenous groups in Mexico, each with a unique language, although certain languages have multiple dialects which may be mutually unintelligible. In 2005, the indigenous population was estimated at 12 million, some 11% or 12% of the national population. The majority of the indigenous population is concentrated in the central and south-eastern states.