In Bolivia, archaeologists have found an ancient city that covers more than 200 km² . For centuries, the city has been hidden with the dense vegetation of the Amazon, and only now have scientists been able to explore it with LiDAR scanners.

As a result, they saw pyramids, dams, canals, elevated “forest islands” and buildings, the location of which hints at the cosmological worldview of the locals. They were built by the Casarabe culture, the indigenous people of these lands in the period from 500 to 1400 AD. At that time, they inhabited more than 4,000 km of the Amazon jungle.

A team of scientists led by Heiko Prümers from the German Archaeological Institute in Berlin discovered the remains of two large settlements called Cotoca and Landívar, as well as 24 small sites, 15 of which were previously unknown. The new results contradict the view that the Amazon was sparsely populated in pre-Hispanic times.

“The architectural layout of large settlement sites of the Casarabe culture indicates that the inhabitants of this region created a new social and public landscape through monumentality. We propose that the Casarabe-culture settlement system is a singular form of tropical agrarian low-density urbanism2—to our knowledge, the first known case for the entire tropical lowlands of South America,” say scientists.

Some settlements were already known to scientists, but a new study has revealed their extensive network of high dams. Such dams stretch for miles through the rainforest. They allowed locals to manage numerous canals and reservoirs.

Two large settlements are surrounded by moats and earth walls. In densely populated areas there are signs of public and ceremonial life: pyramids about 20 meters high and buildings in the shape of the letter U. Such buildings are oriented to the northwest. This, according to scientists, indicates the cosmological worldview of the locals.

Probably there are also smaller villages in the scanned area, too small for the LiDAR to detect. At the same time, the current findings say a lot about the society that built a developed infrastructure in this region and had a rich social life.

LiDAR scanners are powered by laser pulses that point to the ground from aircraft. Scientists record how long it takes for the pulses to bounce off the terrain and return. This allows you to get a detailed topographic picture and find the remains of settlements, even in places where dense vegetation prevents them from being seen with the naked eye and reach them by land.