Separated from the Great Temple, on the north and south sides, there are small altars (two on the north and one on the south). Their peculiarity lies in the fact that they are associated with figures identified as Xiuhcoatl (fire serpent). The heads of the reptiles are carved in stone and emerge from a coiled body of masonry. They accentuate the details of the fangs and emphasize the crest in the form of a volute topped with protuberances. The altars of the Xiuhcoatl correspond to the type of platforms defined as momoztli, that is, small temples located at the foot of or associated with the main temple where ceremonies were held or offerings were placed.

Altar north side

Xiuhcoatl north side

Altar south side

Xiuhcoatl south

It is the most important monument of the site. This pyramidal base of staggered bodies is characteristic of the religious architecture of the Late Postclassic (1200-1521). As in other buildings of its type, the two main deities were worshipped here: Tlaloc, god of rain and maintenance, and Huitzilopochtli, god of war. The temple was enlarged seven times. The oldest took place around 1250, and the last, between 1450 and 1500. Undoubtedly the Templo Mayor de Tenayuca is the most complete of those preserved in central Mexico, and where the religious and artistic expressions of the Nahua people are still preserved.

Last stage of the Templo Mayor de Tenayuca. View from the south

Last stage of the Great Temple of Tenayuca. View from north to south

Templo Mayor de Tenayuca, stairway of the fifth stage of construction

In front of the main temple, on the platform where the stairs are raised, there is a small rectangular altar, also added in the last constructive stage. In three of its sides it has embedded sculptures of skulls and quadrets with the representation of crossed bones. The researcher Alfonso Caso described this altar as the tomb of the solar god. In the interior there was a painting with the same motifs, whose remains were removed to stop the deterioration. However, in the site museum of the archaeological zone, called Xólotl, a reproduction of that painting can be seen today.

Wall of the pyramid where the Altar of the Skulls can be seen

During the last construction stage of the Great Temple, the north, south and east sides were enriched with the platform of the Coatepantli (serpent wall). The bodies of the reptiles, formed with stones and a mortar of lime and mud, were designed with curvatures to appear to be in movement. In the heads, carved in stone, the fangs, the slit eyes and the forked tongue of the reptiles can be appreciated. Another realistic feature is observed in three small steps that top the body simulating the ring or rattle characteristic of the Crotalus triseriatus (rattlesnake). If you look closely, in some specimens there are still traces of the colors (red, blue, black and green) that covered the bodies.