Archaeologists have uncovered a cluster of 2000-year-old cities in the Amazon rainforest.
Laser mapping has revealed that the lost cities were home to around 10,000 farmers.
The cities were inhabited by Upano people between about 500 BC and AD300 to 600, inhabited by at least 15,000 or 30,000 at its peak.
Buildings Erected on 6,000 Mounds
The research published in Science on Thursday journal uncovered buildings erected on at least 6,000 mounds.
The region had a complicated network of roads that stretched for 6-12 miles with a width of 33 feet (10 meters).
Lost Valley of Cities
Archaeologist Stéphen Rostain described the place as a lost valley of cities, with several settlements inhabiting each other not far away from each other.
It would have required an elaborate system of organized workforce to build the roads and thousands of earthen mounds, José Iriarte, a University of Exeter archaeologist, said.
