Another city of the ancient Bajio tradition is Peralta. Restored buildings here are two pyramidal structures with attached fully fenced squares. They are much greater than those that can be seen in the nearby Plazuelas. Archaeologists believe that the visible part is only a small piece of a much larger city, which extended all the way to the other side of a nearby valley, a few kilometers away.
This site has unique elements for Mesoamerica. These are so called “sunken patios.” In opposed to the typical Mesoamerican open courtyards, two squares in Peralta are surrounded by walls and border with temples, in the shape of a rectangular stepped pyramids. Patios were probably used for ceremonial activities. To prevent them from flooding during the rains, the builders did not forget about the drainage system.
It is assumed that natural disasters around the AD 900 resulted in diminishing of the population and forced the remaining inhabitants to abandon Peralta.
