Archaeologists in Mexico have discovered a mysterious underground structure with painted walls hidden beneath a Mayan ball court. The team found the building while excavating a ball court that was a playground for a ritual ball game played by the Mayans and other peoples of Central America.

“We found some parts of an ancient building with painted walls, but only further excavations can reveal the shape and function of this main building,” said Ivan Sprajc, an archaeologist at the Institute of Anthropological and Spatial Studies in Slovenia and director of the Institute of Sciences, who led the excavation.

The find “is clearly a very important structure, since ball courts are usually only found in large Maya sites that were centers of regional political organization,” Spreitz told Live Science in an email. The structure may date to the Early Classic period (200-600 AD) and is covered in a layer of painted plaster, according to a statement from Mexico’s National Institute of Anthropology and History.

Spreitz and his colleagues previously surveyed a large area of ​​the Maya lowlands in the Mexican state of Campeche using lidar, a technique that emits millions of laser pulses from a plane. These pulses are then reflected off the ground and beamed back to a machine on the plane, allowing the researchers to map the topography of the terrain.

“We found several ancient Mayan settlements with the remains of residential buildings and temple pyramids,” Spreitz said. In 2023, the team found Okomtun, a lost Mayan city with several large pyramids dating to the Classic Maya period (c. 200-900 AD). According to him, the new site is located in a previously unexplored area south of Okomtun.

The team also discovered another area containing a plaza, a 16-meter (52-foot) pyramid and a rectangular water tank, according to the statement. At the top of the pyramid, archaeologists found a variety of offerings: ceramic dishes; a ceramic leg of an animal, possibly an armadillo; and the tip of a horn knife or spear. According to Spreitz, these offerings were “placed on top of the temple during the Late Postclassic period (the final centuries before the arrival of the Spanish Conquistadors)” from 1250 to 1524.

By the late postclassic period, the central Maya lowlands had already fallen into political turmoil. But “people remained in the region following a crisis in the 9th and 10th centuries that led to a sharp demographic decline caused by overpopulation, soil depletion, climate change (long droughts) and devastating wars,” he said.

“The donation shows that even after most Classic Maya settlements were abandoned, small, impoverished groups of people still made offerings on or near their ancestral buildings,” Spreitz said.