Ancient Amazon

Lidar keeps rewriting the Amazon.

The “lost cities” were real, complex, and green...

Quick Take: High resolution lidar mapping in Ecuador’s Upano Valley revealed a network of planned towns, platform mounds, causeways, and farmed landscapes dating back about 2,500 years. This adds to basin-wide work suggesting 10,000+ pre-Columbian earthwork sites across Amazonia. The picture is urbanism without stone pyramids...garden cities built in earth, wood, and living soil. Not Atlantis. Very real. Science+2Science+2

What happened

• Upano Valley discovery: A Science paper reports a dense system of pre-Hispanic urban centers with rectilinear streets, platform complexes, plazas, and wide roads extending for tens of kilometers. Occupation spans roughly 500 BCE to 600 CE. Science+1
• Basin-wide context: Separate modeling and remote sensing work estimates more than 10,000 earthwork sites still hidden under canopy, from geometric enclosures to causeways and waterworks. Science+1
• Newsroom confirmations: AP and other outlets highlight the population scale and road grids, grounding the Science results for general readers. AP News

Why this matters

• It resets the old narrative: For decades the Amazon was framed as thinly populated wilderness. Lidar, archaeology, and soil studies show large, organized societies designing landscapes at scale. Science+1
• A different kind of city: These were low density, agriculturally integrated urban systems using earthworks, orchards, fish weirs, and engineered soils like terra preta, not marble and brick. That model matters for sustainability debates today. The Guardian

What we know vs what we do not

We know

• Planned layouts, straight roadways, and clustered platform mounds are mapped across multiple valleys, not a one-off.
• Many features align with intensive food production and water management, implying year-round residence and coordinated labor. Science+1

We do not know

• Exact population totals, political structures, or how climate swings and disease shaped booms and declines.
• How representative Upano is of other yet-unmapped regions. More lidar is coming. PLOS

Pushback and cautions

• Lidar reveals shapes, not dates or meanings. Ground surveys and excavation are required to avoid over-interpreting rectilinear geometry. Scholars also warn against “lost civilization” sensationalism that erases living Indigenous histories. PLOS+1

What to watch next

• New lidar blocks across western Amazonia that may connect known hubs.
• Soil chemistry and paleoecology tying urban grids to orchard species and terra preta formation.
• Comparative studies with Bolivia’s Casarabe culture for shared planning rules. PMC

What if

What if this is the dominant urban blueprint of the humid tropics?
Then the Amazon’s past becomes a playbook for low density, food-integrated cities that maintain biodiversity while supporting large populations. Lessons would move from myth to design principles for modern planners. The Guardian