How did lasers reveal tens of thousands of hidden Maya buildings under the jungle?

Lidar maps the ground hidden under the trees. A scanner fires laser pulses at the ground and measures the time for the reflected light to return; the data can digitally remove the tree canopy, and in 2018 a team of 18 scholars, funded through the PACUNAM foundation, used it to find more than 60,000 man-made structures (61,480 by their count) in the Maya Biosphere Reserve of northern Guatemala, a "major breakthrough" showing that the Maya civilization was much larger than previously thought. Lidar can produce high-resolution datasets quickly and cheaply, and it can map features under forest canopy.

Why was it needed? The dense Maya forest covers northern Petén and Belize, most of Quintana Roo, southern Campeche and part of Yucatán state, and it hides ruins well. Even Tikal, which had been completely mapped as covering more than 16 square kilometres with about 3,000 structures, turned out to be bigger than previously thought once the canopy was digitally stripped away. In 2016, lidar mapping of Maya causeways in northern Guatemala had already revealed 17 elevated roads linking the ancient city of El Mirador to other sites. In 2024 archaeologists found another Maya site, Valeriana, simply by re-reading lidar data collected in 2013 for forest monitoring.

The biggest effect is on how we picture ordinary people. Commoners are estimated to have been over 90% of the population, but relatively little is known about them, and their low-status dwellings can only be detected by extensive remote-sensing surveys of apparently empty terrain. The 2018 team estimated that 7 to 11 million Maya lived in northern Guatemala in the late Classic period, though such estimates are debated.