The geoglyphs of the Brazilian rainforest and the deserts of Chile continue to be threatened by careless human activity. The ancient earthworks—giant geometric or anthropomorphic drawings in the land created thousands of years ago using stones and mounds of dirt—are primarily visible from the air and were largely unrecorded until recent advances in satellite-imaging technology.
In recent years, industrial farmers and ranchers in Brazil have been ploughing over geoglyphs in the Amazon. Deforestation has made many of the geoglyphs visible for the first time, only to be marred shortly thereafter. Meanwhile, off-road racers in Chile have made cuts across the geoglyphs in the Atacama Desert near the city of Iquique. A push for Unesco protection could assuage some of the damage in Brazil, but the future of the Chilean geoglyphs hangs in the balance.
As Brazil prepares to host the 2025 Climate Change Conference (Cop30) in Belém in November, talks around deforestation in the Amazon and the effects of encroaching agricultural development are expected to dominate the summit. But it remains unclear whether officials will propose a plan for the preservation of archaeological sites that have been threatened amid the environmental destruction, including a vast number of ancient geoglyphs that remain understudied and unrecorded.
Since the 1970s, archaeologists have documented nearly 500 geoglyphs in the Amazon, although an estimated 16,000 remain undiscovered. Geoglyphs are found throughout the Amazon and around the world, but a particular concentration exists in the Brazilian state of Acre, where agriculture makes up nearly 20% of the economic sector and archaeological sites are seldom protected.
Aerial views of the Acre geoglyphs in Brazil reveal not just their size but also their precise geometry Pulsar Imagens/Alamy stock photo
The geoglyphs in Acre span an area of around 13,000 sq. km. Archaeologists believe that there were previously more of them, destroyed to make room for cash crops (soy, in particular, has been on the rise lately). This has happened both before and after a federal law regulating the protection of archaeological monuments was enacted in 1961. Scientific study of the geoglyphs took off in the 2000s with a rise in their aerial documentation, and in the past decade there have been efforts to nominate the known Acre geoglyphs for Unesco World Heritage status. However, none has been listed since the nomination was submitted in 2015, and many more geoglyphs have been discovered in the interim.
Antonia Barbosa, an archaeologist with Brazil’s National Institute of Historic and Artistic Heritage (Iphan), began researching the Acre geoglyphs in the mid-2000s, when an increasing number of them were identified. She is unsure whether the geoglyphs will be discussed at Cop30, although her team plans to begin later this year updating the Unesco nomination—it had previously listed only around 300 known sites. According to Barbosa, that process was slated to start in 2024 but halted due to lack of funds. (A representative for Unesco was not available for comment.)
A renewed Unesco nomination will likely emphasise that the geoglyphs rewrite the history of humans in the region, previously thought to have been hunter-gatherers and semi-nomadic groups. “The geoglyphs tell the stories of our ancestors,” Barbosa says. “Constructing sites of this magnitude could not have been the work of one or two people. Their monumentality and sophisticated construction demonstrate that this region of the Amazon, often referred to as the ‘Amazonian sea’, was not an empty space but rather inhabited by people who understood geometry and engineering and lived in complex societies far beyond what we imagined.”
She adds: “The importance of these sites lies in their monumentality, their structure and the perfection of their geometric shapes—their squares, circles and squares within squares. This entire spatial arrangement was created on a grand scale.”
Farming and deforestation
The most immediate threats to the geoglyphs come from agricultural and livestock producers who wrongly perceive so-called “consolidated” areas as exempt from environmental surveys. They tend to support deforestation as well, arguing in favour of industrial farming’s economic benefits. A controversial ruling enacted in 2012 gave farmers the freedom to clear more native vegetation on their land, reducing the area legally required to be preserved on private property from 80% to 50%; this affected around 15 million hectares of the Amazon. The ruling also pardoned illegal deforestation that had occurred prior to 2008.
“Most of the geoglyphs that have been discovered are contained within consolidated and deforested land, although the lack of discoveries in forested areas doesn’t mean there aren’t sites there,” Barbosa says. Some of the first geoglyphs were identified through satellite images, but technological advances like light detection and ranging scanning mean that researchers are now gaining a better sense of what could be hidden in forested areas. (In the neighbouring Peruvian desert, home of the famous Nazca Lines, drones and artificial intelligence recently helped archaeologists discover more than 300 previously unknown geoglyphs.)
Penalties for the destruction of archaeological sites in Brazil vary widely but are rarely enforced. Furthermore, industrial farmers and ranchers may be willing to pay fines if they think they can make up for money lost in long-term profits. Barbosa says that dealing with the defacement of geoglyphs “depends on the type, relevance and importance of the site. One of the first steps is determining whether the site can be restored. If it cannot, measures for compensation or damage mitigation must be taken. Each case is unique and requires specific analysis to assess what has been destroyed and what remains intact.”
When an archaeological site is identified, the landowner may agree to a “term of conduct adjustment” to determine how to compensate for and alleviate the harm caused. However, some landowners refuse to comply. In those cases, a lengthy process is initiated involving federal prosecutors who try to reach an agreement with the landowner. Failing that, a lawsuit is filed. This process can take up to ten years. By then, the geoglyphs in question may be long gone.
Racing to protect Alto Barranco
Geoglyphs in Chile are also facing threats due to human-caused factors, albeit of a different kind. Recently, archaeologists have been seeking to raise awareness of the slow destruction of the 3,000-year-old Alto Barranco geoglyphs in the Atacama Desert. These have been threatened since the 19th century, when gold prospectors excavated some of the structures, believing them to mark hidden treasure left by ancient Indigenous peoples. The geoglyphs’ defacement accelerated with the rise of infrastructure development for copper mining in the 1990s, when off-road racing also became popular in the region. At times, the remote sites have even been used by the Chilean armed forces for bomb-testing.
The Chilean anthropologist and archaeologist Gonzalo Pimentel founded the Atacama Desert Foundation in order to secure the future existence of the geoglyphs, which he describes as “monumental images of the imaginaries and social memory that ancient Andean caravanners inscribed on the hillsides during their trans-desert crossings”. Pimentel and his foundation have continuously denounced events like the 2014 Dakar Rally, an off-road race with more than 400 vehicles that caused significant damage to the geoglyphs. These kinds of races continue to take place in the region, both legally and illegally, further defacing the earthworks every time.
Unlike sites that have been extensively studied (like the Nazca Lines), the Alto Barranco geoglyphs lack Unesco status and their preservation is very loosely enforced. Achieving Unesco status, however, is “putting the cart before the horse”, Pimentel says, since the Chilean government appears not to be committed to the study and protection of the ancient sites. He adds that a preservation plan “must involve serious collaboration with various local stakeholders, as well as a state committed to providing the necessary resources. This seems unlikely in the current context of our ultra-neoliberal state.”
Pimentel further notes that there are “thousands of images scattered throughout the desert, yet there is still no complete inventory of the number of geoglyphs that exist. It is necessary to begin with a national policy plan aimed at their study, protection and social valorisation. These are messages, most of which remain undeciphered, left for the future.”
