A team led by Martti Pärssinen of the University of Helsinki has uncovered evidence of a sprawling pre-colonial civilization in the Amazon basin, challenging long-held assumptions that the region could not support large populations.
Published in Nature on July 30, 2026, the study used LiDAR scanning to identify more than 400 previously unknown earthworks in the Brazilian state of Acre. Researchers estimate 24,000 to 30,000 such structures may exist across 183,000 square kilometres, roughly two-thirds belonging to the Aquiry culture, which thrived between 100 and 300 AD. At its peak, the civilization likely supported 1.25 to 3 million inhabitants in an area covering less than three percent of the Amazon.
The geoglyphs, built between 600 BC and 850 AD, range from 0.35 to nearly 50 hectares. No defensive structures were found, and the discoveries stand in contrast to anthropologist Betty Meggers' 1971 characterization of Amazonia as a "counterfeit paradise" incapable of sustaining complex societies.