Colorado State University archaeologist Chris Fisher found out about lidar in 2009. He was surveying the ruins of Angamuco in west-central Mexico the traditional way, with a line of grad students and assistants walking carefully while looking at the ground for bits of ceramics, the remains of an old foundation or even a tomb.

He had expected to find a settlement, but instead he happened upon a major city of the Purepecha empire, rivals of the Aztecs in the centuries immediately preceding the Spanish conquest of Mexico in 1519.