Among the most well-known examples of Maya architecture are the Mesoamerican civilization’s towering pyramids, which can be found in Guatemala and Mexico. But centuries prior to these iconic temples’ construction, members of the Maya culture built larger—albeit flatter—ceremonial spaces.

Now, thanks to novel aerial imaging technology, scientists have discovered the earliest and largest such ceremonial structures ever built by the Maya. The long-forgotten platform is located in an area called Aguada Fénix, Tabasco, Mexico, and it’s estimated to have been built between 1,000 and 800 B.C.

According to a team of archaeologists led by the University of Arizona’s Takeshi Inomata, the structure is not made of stone, but rather of clay and earth from different sources, suggesting that multiple communities worked together to build the mound and that it was probably used for mass rituals.

The researchers found the platform and at least nine raised roads leading to it with the help of LiDAR, which sends thousands of laser pulses toward the ground each second. By measuring how long it takes for light to bounce back to the transmitter, the technology creates a topographical map of the ground.

LiDAR is often employed in dense jungles. But Aguada Fénix was hidden in plain sight under Tabasco’s semi-forested ranch land. “This area is developed—it’s not the jungle; people live there, but this site was not known because it is so flat and huge,” Inomata explained.

The platform is about nine-tenths of a mile long, a quarter-mile wide, and roughly 3,000 years old, making it the “oldest monumental construction ever found in the Maya area and the largest in the entire pre-Hispanic history of the region,” writes Inomata and his colleagues in the journal Nature.