Surrounded by four platforms, known as the Ciudadela(Citadel) is the temple of Quetzalcoatl. Twice extended upwards, it is principally distinguished by its original 366 sculptures, a rarity in a city in which very few stone sculpture have been found. To whom this shrine was actually consecrated is not known, except that it has some connection with rain and maize.

One of the two alternating types of sculptures is that of a serpent; its head is framed with blossom leaves or feathers, its body surrounded by shell and snail motives representing water.

The other type of sculpture is a stylised mask, possibly that of the rain god Tlaloc or a maize god, represented by large round eyes and a pair of fangs.

In 1986 a burial chamber was discovered with the skeletons of 18 priests who, it would appear, underwent ritual sacrifice around A.D. 150. This sensational find offered proof that it was not just slaves and prisoners who were put to death in this way, but also high-ranking personages. The victims whose hands had been tied behind their backs, had teeth inlaid with jade and other precious stones and were surrounded by shells, arrowheads and small clay figures.