A network of "lost" cities located in the Llanos de Mojos savannah-forest of Bolivia has been discovered using a novel new technology.
Built by the Casarabe communities between 500-1400 AD, these ancient cities, with their terraces and pyramids, have been shrouded by the thick canopy of the Amazon rainforest for centuries.
Now, an international team of researchers from the UK and Germany have used LiDAR (light detection and ranging) technology, dubbed "lasers in the sky", to zoom in on an area dotted with elaborate and intricate structures. These include terraces as high as 16 feet (4.9 metres) tall and conical pyramids towering at 69 feet (21 metres). They also found a vast network of reservoirs, causeways, and checkpoints spanning several miles.
450 'henge' earthworks resembling Stonehenge found in Amazon rainforest using drones.
© Photo : Salman Kahn and José Iriarte
The discovery has revealed that Amazonia, previously thought to have been a historically “pristine” landscape, was home to indigenous populations for thousands of years.
“We long suspected that the most complex pre-Columbian societies in the whole basin developed in this part of the Bolivian Amazon, but evidence is concealed under the forest canopy and is hard to visit in person”, José Iriarte from the University of Exeter told media outlets.
He added that the airborne LiDAR laser technology has revealed monumental structures “just a mile apart connected by 600 miles of canals long raised causeways connecting sites, reservoirs and lakes”. The terrain was surveyed with a laser scanner attached to a helicopter, small aircraft, or drone that transmits around 1.5 million laser pulses per second.
Until the late 20th century, the popular theory was that the Amazon region of the Mojos Plains was home to hunter-gatherer tribes, as the area is typically flooded for several months a year during rainy season.
However, decades of research revealing irrigation, earthworks, large towns and causeways and canals cutting across the savannahs point to the contrary.
“This indicated a relatively dense settlement in pre-Hispanic times. Our goal was to conduct basic research and trace the settlements and life there”, said Dr Heiko Prümers from the German Archaeological Institute, who was also part of the study.
In similar use of the LiDAR technology, a team of researchers in 2020 discovered ancient villages constructed between 1300 and 1700 AD laid out like a clock face. The remote sensing equipment was mounted onto helicopters in south Acre state, Brazil.
According to the study, published in the Journal of Computer Applications in Archaeology, this is further evidence the rainforest has long been occupied by indigenous communities.