In 1925, while exploring the remote jungles of the Amazon on a quest to uncover a fabled lost city, British explorer Percy Fawcett and his small expedition party vanished without a trace.
Fawcett, a noted geographer, artillery officer, cartographer, surveyor, and archaeologist, set off into the rainforest accompanied only by his son, Jack Fawcett, and Jack’s best friend, Raleigh Rimell. Their goal was to locate an ancient lost city rumored to exist in the heart of the Amazon that Fawcett and others called “The Lost City of Z.”
While Fawcett and his expedition crew’s fate remains unknown, new advancements in modern archaeological science, propelled by technologies that include unmanned aerial vehicles and LiDAR, are now revealing what could be the archaeological reality behind part of what the ill-fated British explorer sought.
“The reward is that we’re finally finding the ‘lost civilisation’ that explorers like Percy Fawcett were searching for a century ago,” says José Iriarte, a professor of archaeology at the University of Exeter, writing in a piece featured at The Conversation, though adding that such discoveries are now being made “by cajoling a drone rather than battering through jungle.”
LiDAR: Unearthing Lost Worlds Hidden from Time
For a time, archaeologists presumed that the Amazon rainforest was a vast wilderness that, while abundant in resources, would have been capable of supporting only small, scattered communities.
With the aid of modern technologies, those past ideas have gradually changed as new archaeological evidence continues to push researchers toward rethinking past assumptions. Among these technologies is advanced laser-mapping technology known as LiDAR (light detection and ranging), which archaeologists have put to great use in the last several decades to aid in uncovering evidence of surface features that were once either inaccessible or otherwise invisible during ground-based surveys.
Something else that LiDAR excels at is penetrating the dense forest of areas like the Amazon, enabling researchers to get unprecedented aerial views of the surface below the canopy, along with any structures that may have been left there by humans from long ago. The result has been evidence of sprawling ancient societies hidden beneath the cover of thick jungle, revealing the Amazon as a region that once supported large populations that existed in sophisticated, interconnected landscapes.
Rediscovering a ‘Lost Civilization’ in the Amazon
A particularly striking example of such discoveries involves the Llanos de Moxos region of northern Bolivia, where recent LiDAR surveys have revealed the presence of a sprawling archaeological site long hidden by dense jungle. Archaeologists believe the ancient settlement is linked to what is called the Casarabe culture, which would have thrived in the area sometime between A.D. 500 and 1400.
“The Casarabe organized into a hierarchy of four different sizes of settlements,” writes Professor Iriarte in his recent piece at The Conversation. “The biggest ones—the primary settlements—were as large as 3km² or 300 hectares.”
“That’s enough space for over 400 football pitches,” Iriarte notes, “suggesting that they could have accommodated substantial numbers of people.”
Unseen Evidence of an Ancient Amazonian Culture
Viewed from the ground, an observer who braved this dense region of Bolivian jungle might only see thick patches of forest separated by grassland savannahs.
That all changes when viewing LiDAR imagery obtained during aerial surveys, however. Through the sensitive detection capabilities afforded by laser pulses that can easily penetrate the dense vegetation, a lost world emerges—one the likes of which Percy Fawcett and other early explorers once only dreamed of rediscovering.
Researchers have now successfully identified a vast network of settlements at Llanos de Moxos, connected by raised causeways, canals, reservoirs, and engineered agricultural systems that cover an area of close to 20,000 square kilometers.
These complexes upend past thinking about the presence of isolated settlements in the region, and instead appear to show sites covering areas as large as three square kilometers, featuring monumental civic and ceremonial architecture, towering conical pyramids that ascend to heights of 20 meters, and the presence of massive U-shaped structures, which archaeologists believe had likely served as ceremonial structures that once hosted gatherings.
Unprecedented Scale of a Hidden World
Another surprising feature is the scale of the structures archaeologists have uncovered, which they say rivals some of the most well-known monuments like those of the ancient Tiwanaku civilization in the Andes.
Yet, unlike many densely packed ancient cities, the Casarabe landscape also differs in several ways: the unique variety of urbanism it reflects is suggestive of dispersed populations whose connected infrastructure also brought them together through ancient shared water management systems.
“It was clearly all planned and coordinated,” Iriarte explains, adding that the ancient builders at Llanos de Moxos engaged in precocious designs that were intended “not only as living spaces but for integrating the population across the region.” Similar architectural planning has been observed at other ancient sites around the world, which include those assembled by the ancient Maya of Central America, as well as the builders of Angkor across the world in Cambodia.
The “Dark Earth” Enigma
Beyond just architecture and clues to the way of life of these ancient societies, researchers are also gaining new insights into the agricultural practices of the early Amazonian world.
For many decades, scientists presumed that a major limiting factor on the region’s ability to sustain larger populations hinged on the presence of factors that included poor soils, seasonal flooding, droughts, and tropical diseases. However, mounting evidence suggests that the indigenous societies of the region were far from hindered by the landscape, and instead managed to transform and manage farmland at scales previously unimagined.
Along with sophisticated agricultural systems, ancient Amazonians were also capable of engineering remarkably fertile soils, known as Amazonian Dark Earths, which Iriarte says “combined charcoal, bone and waste materials with the existing poor-quality soil to make it fertile enough for widespread farming.”
“Amazonia had reclaimed vast expanses of seasonally flooded savannahs over several thousand years to create raised and drained field systems,” he adds, also noting the construction of extensive drainage networks and the cultivation of diverse crops such as maize. Rather than merely adapting to the rainforest, the ancient inhabitants of the Amazon actively reshaped it.
An Amazonian Archaeological Revolution
Thanks to similar LiDAR surveys that have recently been undertaken in nearby countries, including Ecuador’s Upano Valley, where thousands of structures linked by roads and organized according to highly structured settlement plans have been detected, the recent findings at Llanos de Moxos are one of the latest additions to a broader revolution in archaeology made possible through such exciting Amazonian discoveries.
In addition to Bolivia and Ecuador, researchers have also documented ceremonial earthworks, geometric enclosures, and sprawling ancient settlements in Colombia, Peru, and Brazil in recent years, all of which are challenging decades of past assumptions about ancient life in the Amazon.
Despite the recent advancements in our understanding, many questions remain unanswered. Among the questions archaeologists have are those related to how these ancient societies were governed, as well as what factors led to their decline, a fall which was precipitated by unknown factors that occurred before European arrival.
Possible contributing factors may include shifts in ancient climates, as well as environmental pressures. It is also possible that political changes or conflicts that emerged between neighboring societies may have played a role, which could have contributed to disruptions in trade networks that may have further weakened these once thriving societies.
Despite the remaining mysteries about these enigmatic cultures, one thing is becoming increasingly clear: the Amazon was far from being the unclaimed tropical wilderness many long believed it to be. In many ways, the fascination with lost cities and ancient civilizations that drove explorers like Percy Fawcett—and which led to his untimely fate—had more basis in reality than many historians, archaeologists, and explorers probably guessed.
As ongoing LiDAR surveys continue to expand across previously unexplored regions, archaeologists believe thousands more structures may still await discovery, suggesting that some of the Amazon’s greatest archaeological secrets remain hidden, but no longer kept entirely from view.
“What lies beneath the Amazon is not just a hidden past,” Iriarte says. “It is a reminder that even the most seemingly untouched landscapes can carry deep histories, waiting—sometimes just beneath our feet—to be revealed.”
Professor José Iriarte’s complete article appeared at The Conversation on June 8, 2026.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.