It is a set of buildings of great relevance because it forms a unit with the North Ball Court, the Polychrome Altar Hall, and a Temazcal or steam bath; in addition to being the space made up of several natural cavities, the best known is the Pre-Hispanic Observatory.

North Ball Court It is the largest of the entire site, having walls up to 12 meters high. The rings that were originally attached to the walls can be seen in the central part.

Temazcal or steam bath It is the most splendid and best preserved found so far in all of Mesoamerica, it was related to the rites of purification, and preparation prior to the game. Quadrangular in shape, it must have had capacity for about 15 people simultaneously, and inside is preserved the space where the stones were heated using firewood. Its organic material roof has been destroyed over time.

Polychrome Altar Hall It was a huge rectangular space whose flat roof was supported by enormous square columns. Inside, the Polychrome Altar was built, a kind of high bench, decorated with paint, on a flattened limestone with motifs of precious waters, and sacred beads, it is believed that purification rituals were performed on this altar, later associated with passing through the Temazcal to finally access the Ball Court to complete the ritual processes.

Cisterna The evidence of water collection that fell from the rain in Xochicalco is evident in this space that served to store this precious liquid, product of the underground conduction from the upper part to this point.