Pyramid of the Moon Project 1988 - 2004

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photo of the Pyramid of the Moon

The objective of this project was to investigate the exterior of the pyramid and explore, by means of excavation tunnels, the earlier buildings in the interior of the pyramid. The structures, burials and offerings discovered and examined during the project provide information about the rituals and beliefs of the ancient Teotihuacanos; the dimensions and dates of the pyramid; and the activities carried out in the pyramid's immediate vicinity.


The Pyramid of the Moon Project was initiated in July of 1998. The first step in the exploration of the pyramid consisted of the excavation of a tunnel into the pyramid from west to east and test pit/trench excavations around the pyramid.

The entrance of the tunnel was located on the west side of the pyramid at the juncture of the Adosada platform with the main body of the Pyramid of the Moon.

The objective of the excavation was to investigate the earlier buildings in the interior of the pyramid and to reach the central area of the buildings to locate any offerings or burials that could provide information about the rituals and beliefs of the ancient Teotihuacanos. Therefore, we excavated tunnels following the Teotihuacan E-W orientation and N-S center line of the pyramid, which is also the main axis of the city.

Two additional tunnels were excavated at higher levels to investigate the upper portion and three-dimensionally central area of the pyramid. As a result of the tunnel excavations seven overlapping structures and three offering-burial complexes were discovered. They have been designated Buildings 1 through 7 from the older to the later, and Burials 2, 3 and 4, which correspond to Buildings 4, 5 and 6 respectively. Burials 5 and 6, found at higher levels, corresponded to the time of termination of Building 5 (or the foundation of Building 6) and the construction period of Building 4 respectively.

At the same time that the interior of the pyramid was being explored systematically and intensively by means of tunnels, the exterior of the pyramid and its associated structures were also investigated. On the north (or posterior), east, and west sides of the Pyramid of the Moon, trenches and pits were excavated in order to confirm the existence of interior and/or adjacent structures. The information recovered from these locations helped establish the exact dimensions, form, and the dates of the pyramid in its earlier versions, and understand activities that were carried out in the immediate vicinity of the pyramid.

Excavation of the Tunnels

The Pyramid of the Moon is a solid building, which was constructed using stones, adobe bricks and earth as fill. The excavation of the tunnels in the pyramid was carried out by local experts using steel bars, picks and rods designed especially for removing the fill from the pyramid.

For safety purposes, a wooden roof was constructed approximately every 1 to 3 feet as the excavation progressed, in order to retain the fill. The location of all wooden posts that were placed in the tunnels as support structures, as well as all the other relevant architectural informatio,n was mapped using a total station. The data was then used to develop three-dimensional maps.

In the process of excavating inside the Pyramid of the Moon some of the walls of the previous buildings were discovered. We therefore knew that the ancient Teotihuacanos periodically remodeled the pyramid. With each remodeling, the existing building was covered by a new one, so that each previous building actually served as fill for the new construction. The information obtained made it possible to reconstruct the shape and dimensions of the structures at the plaza level.

The route of the tunnels is carefully laid out with the help of a three-dimensional map we were creating at the same time. Using this information, it was possible to reconstruct the buildings that have been found during each field season and plan the ongoing and future excavation for the following field seasons as we were finding burials and caches at unexpected locations .

After we concluded the tunnel operation at the Plaza level, we calculated the height of earlier structures covered later with the fill of the Moon Pyramid, from the data obtained in the lower tunnel, and excavated a new tunnel at the level of the proposed upper floor of Building 5 in 2000-2 (Front H). As a consequence, we encountered well-preserved west façade wall and the upper floor of the building. During the tunnel excavation following the stuccoed floor, we discovered and completely explored a large burial/offering complex in well-preserved condition with rich symbolic objects. We also explored three-dimensionally the central area of Building 4 by a new tunnel operation to verify hypothetically proposed burial at its center (Front K). Burial 6 was found and explored in 2003-4 that provided critical information about the state ideology and social history of the ancient city in Teotihuacan.

Superimposed Buildings

The tunnel operation by the Pyramid of the Moon project has made possible the identification of seven superimposed structures at the pyramid.

We now know that the ancient Teotihuacanos periodically enlarged and/or modified the pyramid. With each modification, one building was covered by another successively so that each time the earlier building served as fill for the new construction.

The first structure was small in comparison with later structures, and is located under the Adosada platform of the current Pyramid of the Moon. The shape of this structure, like the three structures that subsequently covered it, was square. The increase in size of the pyramid in the second and the third stages of construction was gradual, but the fourth structure was substantially enlarged, covering an area nine times larger than the third one. The construction may have marked a crucial moment in the political organization of the city.

The construction of the fifth building must have also marked an important moment in the interest of the ruling group since the form of the pyramid underwent a significant change. Beginning with this fifth structure, and continuing with each of the following structures, the building consisted of a main square platform with a smaller platform attached on the south side – the "Adosada."

The construction of the sixth building marked a significant enlargement of the pyramid towards the north, east and west, nearly reaching the size of the seventh structure, which is what we see today. The seventh remodeling of the pyramid was the last that continued to be used until the moment of the fall of the city, as later constructions were found attached to its sides or in the immediate areas.

In some instance of remodeling, a burial/offering complex was placed on the north-south axis of the pyramid. Burials 2 and 6, Burial 3 and Burials 5 and 4 were integrated at different vertical levels that corresponded to the foundation moment of Buildings 4, 5 and 6 respectively. The offering complexes set carefully in symbolic spatial arrangement were exceptional in quality and quantity and will provide critical information to reconstruct the state ideology of ancient Teotihuacan.

Exterior Structures of the Moon Plaza Complex

The excavation of trenches and pits outside the Pyramid of the Moon was carried out to define the dimensions and stratigraphic relationships of sub-structures, adjacent construction units and the pyramid, and to investigate activities that took place around the pyramid. Pit excavation at the four corners of the Moon Pyramid precisely defined the final footprint of the pyramid and verified that these points did not contain dedicatory tombs, as was the case in the Feathered Serpent Pyramid and Pyramid of the Sun.

A large multi-structure complex located on the west side of the pyramid was extensively excavated. The complex was built on a three-meter-high platform attached to Buildings 6 and 7 of the Pyramid of the Moon, and that covered an earlier construction. The complex consists of a series of rooms, porticos, patios, corridors and low platforms, with its central talud-tablero structure oriented facing south (Fig. 8). Very dense quantities of obsidian debris were encountered in the nucleus of the complex.

Among the many operations of the Pyramid of the Moon project, one of the medium-size pyramids surrounding the Moon Plaza was explored through a tunnel excavation at subsoil level (Fig. 9). The tunnel started from the northern façade of the pyramid (Structure 1:N5W1, according to Millon et al. 1973) and extended south, revealing that there were at least six construction levels. Each level had quite different dimensions, form and construction systems, indicating that the Moon Plaza complex also had a long history of complicated modification and architectural elaboration.

Burial 2

Burial 2 was a large burial complex with abundant offerings of exceptional quality discovered just north of the northern façade of Building 3, in line with the north-south axis of the Avenue of the Dead.

The interior of the grave was completely filled with a homogeneous earthen layer. Inside we discovered the remains of an individual who had been tied with arms crossed behind the back prior to deposition; the complete skeletons of two pumas, one wolf, nine eagles, rattle snakes; and the incomplete remains of other animals. These ossuary remains were associated with a large number of offerings of exceptional quality and quantity, evidently set carefully and symbolically on the floor (Fig. 11).

Among the offerings were diverse objects of obsidian, greenstone, pyrite, shell and ceramic. Stratigraphic information indicates that the burial complex was prepared during the construction of Building 4. Therefore, we believe that the individual and animals were sacrificial victims buried together with the offerings in dedication of the monument.

The evidence indicates that the animals were probably alive when they were deposited in Burial 2. One of the indications of this is that the two pumas and the wolf were found surrounded by what appeared to be the imprint of a cage. Apparently it was necessary to place them in the cage because they were alive (Fig. 12).

Burial 3

An offering-burial complex was found in line with the central north-south axis of the Avenue of the Dead associated with Building 5 at the Pyramid of the Moon. In this case the offering-burial complex, consisting of the bodies of sacrificial victims covered with abundant offerings, was deposited in a large pit that had been excavated in the natural tepetate. The location of the deep burial pit within the tunnel made excavation difficult and required major security precautions.

Four individuals were placed parallel to one another in an east-west direction. All had their arms crossed in the back as if they had been tied at the wrists. Three of them were found in an extended position and the other was flexed to the left side.

The buried individuals wore ornaments of shell and greenstone, such as earrings, beads and a nosepiece. This offering complex was found completely covered with large stones, which explains why the skeletons were found poorly preserved.

Among the objects found deposited over the skeletons of the individuals were figurines of green stone, very large conches (Pleuroploca gigantean), a large pyrite disk, organic fibers and numerous obsidian figurines, knives and miniature projectile points (Fig. 15). The animals found in the offering consisted of feline and canine heads and the skeleton of an owl.

Burial 4

Burial 4 was found in the fill of Building 6 at the Pyramid of the Moon on the central axis of the Avenue of the Dead, and was made up of 17 human crania of individuals who were decapitated. There may have been an eighteenth cranium, since a vertebra (atlas) was found that did not belong to the other individuals, but the cranium itself was not located. The burial did not contain any associated offerings, and the arrangement of the burial was not as careful as in other burials found inside the Pyramid of the Moon.

Burial 5

A large grave pit was discovered on the upper floor of Building 5 during excavation of the Pyramid of the Moon's upper tunnel in 2001. The pit was found completely filled with stones, rocks and earth, which were immediately covered by the Teotihuacanos with the construction nucleus of Building 6. Therefore, we interpret that the grave was originally set up for a termination ritual of Building 5 and at the same time formed a part of the foundation ritual of Building 6 that they had already planned to construct.

We intensively explored Burial 5 during the 2001-02 field seasons, constructing an iron scaffold inside the pit with a solid metal roof for protection from loose rubble. Once the scaffold was in place, we uncovered the remains of three high-status individuals, animals and a large quantity of atypical offerings, including Maya-style greenstone objects. In particular, we recovered two large rectangular jadeite pectorals, earspools and large beads that are unique among objects found previously in Teotihuacan, but were common symbols of rulership among the ancient Maya societies.

Additionally, the three individuals were buried in cross-legged seated position, indicative of very high social status. Although it is difficult to ascertain who they were, the burial context indicates that the Teotihuacan leaders responsible for the grave preparation had direct interactions with Maya dynasties that controlled the production and distribution of jadeite prestige items in Guatemala.

Burial 6

In 2003, we opened a new tunnel from the upper floor of the Adosada platform descending into the intermediate platform (to the north) in order to explore the three-dimensional center of Building 4/5.

As was expected, we encountered the southern edge of a grave complex (Burial 6), but we had to wait until summer 2004 to explore it completely. After again constructing an iron scaffold inside the pit with a solid metal roof, we intensively explored lower layers of the grave to uncover one of the richest dedicatory burials at Teotihuacan.

The grave, encircled by stone walls on all four sides, contained 12 individuals, many animal remains and exceptionally rich offerings. All 12 individuals were evidently victims of a sacrificial ritual; they were found with their hands in a tied position behind their backs, and 10 of them completely lacked their cranium and first cervical vertebras, indicating that they were decapitated when the bodies still had flesh.

The data again indicated the importance of sacrificial rituals and militarism. Among many outstanding objects included in Burial 6 were nine large curved obsidian knives, nine feathered serpent figures of the same material, a greenstone mosaic human figure, more than 50 sacrificed animals and abundant symbolic items made with obsidian, shell, ceramic and organic materials.

photo of Professor Saburo SugiyamaProject Director: Saburo Sugiyama, ASU School of Human Evolution and Social Change
Project Director: Ruben Cabrera, Mexican National Institute of Anthropology and History