Archaeologists find 2,000-year-old 'lost valley of cities' in Ecuador's Amazon

Archaeologists have discovered a set of lost cities in Ecuador's Amazon rainforest that were home to at least 10,000 farmers around 2,000 years ago.

A series of earthen mounds and buried roads in Ecuador were 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 he, one of the researchers who reported the discovery Thursday in the journal Science.

Recently, mapping using laser sensor technology revealed that these sites are part of a dense network of settlements and connected roads, hidden in the forested hills of the Andes, that lasted about 1,000 years. “It was a lost valley of cities,” said Rostain, who leads the investigation at France’s National Center for Scientific Research. “It's incredible.”

The settlements were occupied by the Upano people between approximately 500 BC and 300 to 600 AD – a period roughly contemporary with the Roman Empire in Europe, the researchers discovered.

Residential and ceremonial buildings built on more than 6,000 mounds of earth were surrounded by agricultural fields with drainage channels. The largest roads were 10 meters wide and stretched for 10 to 20 kilometers.

Although it is difficult to estimate the size of the population, 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, co-author of the study, from the same French institute. This is comparable to the estimated population of Roman-era London – at the time, the largest city in Britain.

“This 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 category of its own in terms of how early it is.”

José Iriarte, an archaeologist at the University of Exeter, said it would take an elaborate system of organized labor to build the roads and thousands of mounds of earth. “The Incas and Mayans built with stone, but people in the Amazon generally didn't have stone available to build with – they built with clay. Still, it's a huge amount of work,” said Iriarte, who was also not involved in the research.

The Amazon is often considered to be “untouched nature with only small groups of people”. However, recent discoveries have shown how much more complex the forest's past really was, he said.

Recently, scientists have also found evidence of intricate rainforest societies that predated European contact in other parts of the Amazon, including in Bolivia and Brazil. “There has always been an incredible diversity of people and settlements in the Amazon, not just one way of living,” Rostain said. “We’re just learning more about them.” Source: Associated Press.