How many ruins of the ancient world remain undiscovered? While we marvel at the monuments that have remained ‘in sight’ down through the ages, such as Stonehenge and the pyramids of Giza, it’s worth remembering that there are still many ancient sites that are still hidden, whether by dirt, water, or jungle. In the latter case, archaeologists have begun ‘uncovering’ some of these lost cities using something more high tech than a shovel. With LiDAR (‘Light Detection and Ranging’ – a remote sensing method that uses pulsed lasers to measure the distance to Earth), they can construct a 3D digital map of the location and see through the jungle and locate man-made structures previously obscured from human eyes. Last week a paper in the journal Science announced the discovery of more than 60,000 “ancient structures” that had previously been hidden from view under the lush foliage of the tropical Guatemalan jungle: Lowland Maya civilization flourished from 1000 BCE to 1500 CE in and around the Yucatan Peninsula. Known for its sophistication in writing, art, architecture, astronomy, and mathematics, this civilization is still obscured by inaccessible forest, and many questions remain about its makeup. In 2016, the Pacunam Lidar Initiative (PLI)undertook the largest lidar survey to date of the Maya region, mapping 2144 km2 of the Maya Biosphere Reserve in Guatemala. Analysis identified 61,480 ancient structures in the survey region, resulting in a density of 29 structures/km2. The researchers extrapolated from these figures to (conservatively) estimate that, during the Late Classic period, there could have been at least 2,724,396 structures over an area of 95,000 km2 in the central Maya Lowlands, with a population between 7 million and 11 million. Comparison showing how LiDAR can identify structures beneath dense foliage Furthermore, they found evidence for structures and systems supporting an “agricultural economy of great complexity that would have been crucial in feeding this large population: the landscape “was heavily modified for intensive agriculture”, with grids of drainage channels, some kilometres long, as well as reservoirs, terraces and walls. Overall, the researchers concluded that the data collected… …unambiguously support the notion that the lowland Maya constructed a variable and contentious landscape in which a regionally interconnected network of densely populated and defended cities was sustained by an array of agricultural practices that optimized land productivity, resource diversity, and sustainability on a much grander scale than previously thought. We look forward to seeing what else they discover in future!