There are probably more than 10,000 undiscovered pre-Columbian archaeological sites hidden in the Amazon, researchers have concluded after surveying a fraction of the sprawling rainforest.
The study adds to growing evidence suggesting that the region isn’t a pristine tropical forest, but has been significantly altered by Indigenous societies that have inhabited it for more than 12,000 years.
Luiz Eduardo Oliveira e Cruz de Aragão at the National Institute for Space Research in Brazil and his colleagues surveyed 5315 square kilometres of the Amazon using lidar, a technology that uses reflected laser light to create a 3D representation of a landscape.
By beaming pulses of light into the rainforest, usually from planes or drones, lidar records slight variations in topography and has uncovered numerous archaeological sites in recent years.
The team discovered 24 previously unknown earthworks in the areas it surveyed, which are thought to be the remnants of civilisations that lived between 1500 and 500 years ago.
The discoveries include a fortified village in the southern Amazon, a region known to have been densely populated due to the high concentration of earthworks that were connected by ancient roads.
Defensive and ceremonial sites in the southwestern Amazon were also brought to light, along with permanent settlements and ceremonial sites with large stone structures arranged in circular clusters in the northern Amazon.