Huapalcalco

Huapalcalco is a pre-Columbian Mesoamerican archeological site located some 5 kilometers north of Tulancingo in the state of Hidalgo, Mexico.

The site was built on the west slope of the "Tecolote" hill; the slope is separated east-west by a ravine that forms two sectors at the foot of the hill and two more on the top, all of which contain archaeological vestiges.

The site depicts Teotihuacán influence, and some believe that Topilitzin Quetzalcóatl resided here, before governing Tula. Also it is considered the oldest human occupation site in the state of Hidalgo.

Source: Wikipedia