LiDAR survey reveals Amazon rainforest civilization of up to 3 million people unknown to science

LiDAR Survey Reveals 3 Million-Person Amazon Civilization

A new LiDAR survey of Brazil's Acre state has upended assumptions about pre-Columbian settlement in the Amazon, uncovering evidence of a civilization that may have supported between 1.25 million and 3 million people—far larger than previously thought.

The survey mapped 4,500 square kilometers of rainforest after flying 4,400 kilometers, using laser scanning technology that penetrates dense forest canopy. Researchers identified 396 previously unknown geoglyphs—massive geometric earthworks made from ditches and raised embankments—and published the findings in Nature.

The earthworks were not permanent villages but ceremonial and civic centers where people gathered for rituals, political meetings, and communal events. The Aquari civilization, believed to have emerged around May and flourished until August, cultivated crops like corn and squash in nearby multifamily longhouses. Population estimates are based on the density and labor requirements of these earthworks.

The scale of discovery is striking. The surveyed area alone contains roughly as many earthworks as earlier estimates suggested existed across the entire Amazon Basin. If future LiDAR surveys find similar densities elsewhere, estimates of pre-Columbian Amazon populations could be revised dramatically upward.

What happened to the civilization remains unknown. The abandonment of ceremonial centers between August coincided with the decline of several other major societies across the Americas, including the Maya, but the causal mechanism is unclear.