The ancient indigenous peoples of South America constructed a series of large earthworks deep in the Amazon rainforest, according to a new study in The Proceedings of the National Academy of Sciences.
An international team of researchers discovered 450 of the aged markings by flying drones over jungles in Acre — a state in northwestern Brazil. Dating shows they were constructed nearly 2,000 years before Europeans set foot on the continent.
The odd circles are geoglyphs, large ground designs made out of rocks or other durable materials like trees and stones. Though the Amazon’s thick vegetation kept the hidden for thousands of years, recent deforestation and development have brought them to light.
This finding is important because it reveals new information about how the ancient people in the area existed before the age of European exploration. In addition, it also challenges the notion that Amazonian jungles are pristine ecosystems.
“We immediately wanted to know whether the region was already forested when the geoglyphs were built, and to what extent people impacted the landscape to build these earthworks,” said lead author Jennifer Watling, a post-doctoral researcher at the Museum of Archaeology and Ethnography, University of São Paulo, in a statement.
To analyze the area around the geoglyphs, researchers reconstructed 6,000 years of vegetation and fire history around two enclosure sites. This showed that humans heavily altered bamboo forests in the region and altered the land for thousands of years. However, they did not use methods like clearcutting or field burning to make room for the earthworks. Rather, they just opened small clearings.
Researchers have only uncovered a few artifacts from the sites, suggesting that the areas — which resemble Neolithic causewayed enclosures found at places like Stonehenge — were not used as shelter. It is much more likely they were used for gatherings and had a spiritual significance of some kind.
“It is interesting to note that the format of the geoglyphs, with an outer ditch and inner wall enclosure, are what classically describe henge sites. The earliest phases at Stonehenge consisted of a similarly laid-out enclosure,” added Watling, according to Tech Times.