In northern Guatemala lies a hidden city devoured by the wild, relentless jungle. Local people discovered strange hills arranged in massive circles. Archaeologists realized this was the religious and cultural center of the Mayan Civilization. Some of these ruins are being brought to life with the aid of satellites and a laser scanning technology called LiDAR. In the past year, LiDAR images unveiled an astonishing but hidden jungle metropolis. Homes? highways? defensive walls? pyramids. In all, more than 60,000 structures, their outlines invisible to the naked eye. Taken together, they point to a far more sprawling and sophisticated civilization than we ever imagined possibleand they raise a provocative question: How could such a great society fail?