CINCINNATI, Feb. 21 (UPI) — U.S. researchers say findings inside a cave in Mexico show the inhabitants of an ancient Mayan city practiced sophisticated water management in a dry region.

Researchers from the University of Cincinnati conducting mapping and excavations at the site on the Yucatan Peninsula say the city — featuring a great pyramid and other elaborate architecture — was built above one of the few cave systems in the region that penetrates the permanent water table.

“This is in a region that has no surface water,” researcher Nicholas Dunning said. “There are only a handful of caves that go deep enough to get to the permanent water table, so for anyplace that’s bone dry for five months out of the year, this is a pretty special location.”

Excavations of the city revealed the cave was part of a network of cisterns and reservoirs that fed the community’s water supply.

Two large reservoirs were located in the middle of the city and the smaller reservoirs and cisterns extended into the residential area and surrounding farmland, the researcher said.

The city was the largest in the Puuc Region of the Yucatan from around 800 B.C. to 100 A.D., but there are significant signs the city was abandoned between 100 A.D. and 300 A.D., most likely due to drought, a university release said.