The ancient civilizations of the Maya in South and Central America and the Khmer Empire in Southeast Asia have long been shrouded in mystery—a mystery partly due to the dense forest canopy that makes these areas inaccessible and difficult to survey by air. This month’s OPN infographic looks at how the technology of light detection and ranging (lidar), with the capability of peeking beneath these forest canopies, is providing a new view of the extent and sophistication of these ancient cities.