Lidar Survey Finds 20,000+ Ancient Earthworks in the Amazon

A July 29, 2026 Nature study used lidar — laser pulses fired from aircraft to map ground surfaces — to identify over 20,000 precolonial geoglyphs in the southwest Amazon near the Brazil-Bolivia border. The scale challenges the long-standing view that the region's nutrient-poor soils could not sustain dense, settled societies capable of organized, monumental construction.