Archaeologists have found thousands of Maya structures and a lost city they named Valeriana in Mexico by using laser mapping technology, according to a new study.

A city with temple pyramids not far from the road and a site with a Maya complex built alongside a sinkhole lend to evidence that the Maya civilization was even more sprawling than known.

Over 6,500 previously unknown Maya structures, including an entire city with towering pyramids, were revealed in southeast Mexico.

Researchers have discovered a previously unknown Maya city in Mexico’s Yucatan peninsula after they used laser imaging of the rainforests to find thousands of ancient structures.

In recent years, LiDAR laser scanning has allowed researchers to analyze large swaths of densely forested land in Mexico in their search for undiscovered ancient settlements and structures, as opposed to conducting the time-consuming, on-the-ground assessments previously required for archaeological surveys.

Auld-Thomas and his colleagues, who published their findings Monday in the journal Antiquity, call the city Valeriana, after a nearby lagoon. They estimate that it may have had a population of as many as 50,000 people at its peak, which was most likely around the end of the late Classic Maya era, probably between about A.D. 750 and 850.

East of the town of Dos Lagunas, past the major highway cutting through Mexico’s south, the forest rises up in a dense wall of grasping roots, spindly branches and veils of brown and green. Beyond it lies the ruins of an old Maya city,

WIRED spoke with the researchers responsible for the discovery of Valeriana, a lost Maya city in the middle of the jungle of Campeche.

Tulane researchers uncovered over 6,500 Maya structures in Mexico using lidar, revealing a complex settlement landscape and challenging previous assumptions about the Maya civilization’s urban and rural distribution.