Teotihuacan (pronounced /ˈtɛɔˌtiwɑˈkɑn/), also written Teotihuacán, was a pre-Columbian Mesoamerican city located in the Basin of Mexico, 30 miles (48 km) northeast of modern day Mexico City, which is today known as the site of many of the most architecturally significant Mesoamerican pyramids built in the pre-Columbian Americas. The name means "the place where men become gods." Apart from the pyramids, Teotihuacan is also anthropologically significant for its complex, multi-family residential compounds, the Avenue of the Dead, and the small portion of its vibrant murals that have been exceptionally well-preserved. Additionally, Teotihuacan produced a thin orange pottery style that spread through Mesoamerica.
The city is thought to have been established around 100 BC and continued to be built until about 250 AD. The city may have lasted until sometime between the 7th and 8th centuries AD. At its zenith, perhaps in the first half of the 1st millennium AD, Teotihuacan was the largest city in the pre-Columbian Americas, with a population of perhaps 125,000 or more, placing it among the largest cities of the world in this period. Teotihuacan began as a new religious center in the Mexican Highland around the first century AD. This city came to be the largest and most populated center in the New World. Teotihuacan was even home to multi-floor apartment compounds built to accommodate this large population. The civilization and cultural complex associated with the site is also referred to as Teotihuacan or Teotihuacano.
The pre-Columbian history of the territory now within the contemporary nation of Mexico is known through the work of archaeologists and epigraphers, and through the accounts of the conquistadors, clergymen, and indigenous chroniclers of the immediate post-conquest period. While relatively few documents (or codices) of the Mixtec and Aztec cultures of the Post-Classic period survived the Spanish conquest, more progress has been made in the area of Mayan archaeology and epigraphy.
Human presence in the Mexican region was once thought to date back 40,000 years based upon what were believed to be ancient human footprints discovered in the Valley of Mexico, but after further investigation using radioactive dating, it appears this is untrue. It is currently unclear whether 21,000-year-old campfire remains found in the Valley of Mexico are the earliest human remains in Mexico. Indigenous peoples began to selectively breed maize plants around 8000 BC. Evidence shows a marked increase in pottery working by 2300 B.C. and the beginning of intensive corn farming between 1800 and 1500 B.C..
Between 1800 and 300 BC, complex cultures began to form. Many matured into advanced pre-Columbian Mesoamerican civilizations such as the: Olmec, Izapa, Teotihuacan, Maya, Zapotec, Mixtec, Huastec, Purepecha, Totonac, Tarascan, "Toltec" and Aztec, which flourished for nearly 4,000 years before the first contact with Europeans.