Hundreds of ancient earthworks resembling the mysterious Stonehenge were found via drones in the Amazon.
The discovery of the more than 450 large geometrical geoglyphs is seen as a proof that hundreds of years ago, indigenous people transformed the rainforest into something different than what we know about the dense foliage today.
The researchers said prehistoric settlers in the western Brazilian Amazon performed deforestation to create the huge enclosures, which occupy approximately 13,000 square kilometers. But they also noted that the alterations did not involve clearcutting or field burning and the indigenous people changed the landscape by encouraging the growth of preferred species.
Science Alert said the clearing occurred about 2,300 and 1,400 years ago, before Europeans arrived. It was also in those years that the first earthworks are thought to have been constructed.
Through analysis of soil samples taken from the site, archaeologist Jennifer Watling from the University of São Paulo in Brazil and her team found out that 6,000 years ago, the soil was covered with bamboo until humans moved 4,000 years ago and palm trees started to cover the land.
"Our evidence that Amazonian forests have been managed by indigenous peoples long before European Contact should not be cited as justification for the destructive, unsustainable land-use practiced today," she said in a press release.
Walting added that the discovery should emphasize the "ingenuity of the past subsitence regimes" and how this could help in finding alternative ways in sustainable land-use.
Meanwhile, the purpose of the earthworks is still not understood until today. What most experts think is that they are used as venue for rituals rather than for defense or shelter. The researchers particulary took note that the earthworks resemble the Stonehenge.
"It is interesting to note that the format of the geoglyphs, with an outer ditch and inner wall enclosure, are what classicly describe henge sites. The earliest phases at Stonehenge consisted of a similarly layed-out enclosure," Watling said.