Archaeologists have discovered a group of lost cities in the Amazon rainforest it was home to at least 10,000 farmers some 2,000 years ago.
A series of earthen mounds and buried roads Ecuador was first noticed more than two decades ago by archaeologist Stéphen Rostain. But at the time, “I wasn’t sure how it all fit together,” said Rostain, one of the researchers who reported the finding in the journal Science on Thursday.
Recent mapping by laser sensor technology has revealed that those sites are part of a dense network of settlements and connecting roads, hidden in the forested foothills of the Andes, that lasted about 1,000 years.
“It was a lost valley of cities,” says Rostain, who leads investigations at France’s National Center for Scientific Research. “It’s amazing.”
The settlements were occupied by the Upano people between about 500 BC and 300 to 600 AD – a period roughly contemporaneous with the Roman Empire in Europe, the researchers found.
Residential and ceremonial buildings erected on more than 6,000 earthen mounds are surrounded by agricultural fields with drainage channels. The largest roads were 33 feet (10 meters) wide and spanned 6-12 miles (10-20 km).
Although estimating populations is difficult, the site was home to at least 10,000 inhabitants — and perhaps as many as 15,000 or 30,000 at its peak, said archaeologist Antoine Dorison, a study co-author at the same French institute. , said. This is comparable to the estimated population of Roman-era London, Britain’s largest city at the time.
![A Lidar image of the Copueno site, Upano Valley, Ecuador.](https://i.guim.co.uk/img/media/144dacd27cfe1ee9e706dcd4ffa7329e228d6439/0_0_2864_3000/master/2864.jpg?width=445&dpr=1&s=none)
“It shows a very dense occupation and an extremely complicated society,” said University of Florida archaeologist Michael Heckenberger, who was not involved in the study. “For the region, it’s really in a class of its own in terms of how early it is.”
José Iriarte, an archaeologist from the University of Exeter, said it would have required an extensive system of organized labor to build the roads and thousands of earth mounds.
“The Incas and Mayas built with stone, but people in Amazonia usually didn’t have stone available to build with – they built with mud. It’s still a tremendous amount of labor,” says Iriarte, who had no role in the research.
The Amazon is often considered an “unspoiled wilderness with only small groups of people. However recent discoveries have shown us how much more complex the past really is,” he said.
Scientists have also recently found evidence of complex rainforest societies that preceded European contact elsewhere in the Amazon, including in Bolivia and in Brazil.
“There has always been an incredible diversity of people and settlements in the Amazon, not just one way of life,” Rostain said. “We’re just learning more about them.”