[5] The architectural style of the building was linked closely to that of Teotihuacan in the Valley of Mexico, although influence from the Gulf Coast is evident as well, especially from El Tajín.

[8] These people kept the pyramid as their primary religious center, but the newly dominant Toltec-Chichimecas founded a new temple to Quetzalcoatl where the San Gabriel monastery is now.

The Toltec-Chichimec people who settled in the area around the twelfth century AD named Cholula as Tlachihualtepetl, meaning "artificial hill".

[10] Over a period of a thousand years prior to the Spanish Invasion, consecutive construction phases gradually built up the bulk of the pyramid until it became the largest in Mexico by volume.

[12] The Postclassic nahuas called the pyramid Tlachihualtépetl or "hand-made mountain", which means they believed the structure was built by human hands instead of by sacred beings.

[15] The Toltec-Chichimec History, a codex from the Cholula region, relates that an Olmec-Xicalanca lord with the title Aquiyach Amapane resided at the Great Pyramid.

The earliest construction phase features talud-tablero architecture that is characteristic of the region, and that became strongly associated with the great metropolis of Teotihuacan.

Most of Bandelier's work involved the unearthing of various burials in the area around the pyramid, principally collecting skulls, which was standard practice at the time.

[26] The pyramid had no obvious entrance, due to its deteriorated condition, but the archaeologists decided to begin tunnelling on the north side, where colonial construction had damaged it.

This solid foundation allowed the excavators to only need to create "false arches" like those found in Mayan constructions, rather than adding beams and other supports.

[28] During the first round of excavations, sixteen holes were dug in the area by Eduardo Noguera to extract ceramic materials and establish a time line.

One major find included a ceremonial scepter carved from bone, with images related to the concept of life and death as a duality.

In addition to the excavating of the main structures of the pyramid, Messmacher, Eduardo Matos Moctezuma and others in the project worked on more multidisciplinary tasks, such as determining agricultural patterns of the site, ceramic development and water distribution systems.

[30] In 1967, INAH decided to replace Messmacher with Ignacio Marquina as head of the team excavating the site, which prompted most of the younger researchers to leave the project.

While the focus was placed back on the pyramid proper, the project did not lose all of its interdisciplinary character, keeping experts in areas such as geology, botany and paleozoology.

The project began to focus on the south side of the pyramid, excavating the remains of plazas and buildings that made up a large complex.

[32] Despite the site's pre-Hispanic importance, this pyramid is relatively unknown and unstudied, especially in comparison to others in Mexico such as Teotihuacan, Chichen Itza and Monte Albán.

There are few signs explaining the structures within, but in one section allows a view of main staircases of one of the pyramids, whose nine floors have been excavated from bottom to top.

The female skeleton is accompanied by grave goods related to domestic life such as comals, bone needles, spindles, and pots.

His grave goods are far richer, with ritual vessels, and elegant vase with a multicolored design, obsidian arrowheads, and a musical instrument called an omexicahuaztli.

One is a pyramidal platform and the other is a talud-tablero structure with a double cornice and crest in adobe, decorated with interlocked designs in low relief painted red, yellow and green.

The structure consists of a very large open area measuring seventy by fifty-four meters, bordered by the pyramid proper to the north, and on the east and west sides by two complicated raised platforms, named Patio Sureste and Gran Plaza Suroeste by the excavators.

These platforms are similar to those in the Northeast plaza, but they are up against the side of the main pyramid, which was done to amplify the patio's hierarchical and ritual nature.

[19] As new phases of construction took place, newer versions of buildings were built over the pre-existing version, covering the lower part and adding a new or modified facade, resulting in the reduction of the courtyard area by the gradual encroachment of the surrounding structures and added several metres to the original platform height.

There is also a giant human head, with the edges of its eyes and mouth marked in a way that resembles Xipe, which could correspond to a post-Olmec tradition, as similar figures were found in Tlaxcala.

[44] The subject of the mural is a ceremony where the participants appear relaxed as they realize various activities, which include drinking, making offerings, serving with one vomiting and one defecating.

The first mural consists of horizontal bands in a reddish ochre and a hook like design in red surrounded by an ellipsis in the same tone over a black background.

[45] Building I was unearthed during a brief period of six months at the beginning of the second round of excavation, mostly by Eduardo Matos Moctezuma and Pablo López Valdéz.

The process yielded a large number of ceramics figurines and vessels, which were studied by Florence Müller and range from the Pre Classic to the Postclassic.

This event can draw up to 20,000 visitors, leading authorities to restrict access to the exposed archeological ruins on the south side.