For centuries, explorers chased the legend of El Dorado - a mythical city of gold said to be hidden somewhere in South America.

06:30, Thu, Aug 6, 2026 Updated: 06:30, Thu, Aug 6, 2026

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Explorers and more recently scientists have been attempting to unlock the mystery of El Dorado (Image: Martti Pärssinen)

A forgotten civilisation that may have been mistaken by Spanish colonists for the legendary City of Gold - El Dorado - has been revealed deep beneath the Amazon rainforest after archaeologists used laser scanning technology to uncover hundreds of previously unknown ancient earthworks.

The society, known as the Aquiry, and which numbered up to 3 million people, emerged in what is now Brazil around 2,500 years ago and built vast geometric structures known as geoglyphs across the rainforest landscape.

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Researchers believe the scale of these monumental earthworks suggests the Aquiry was one of the most complex pre-Columbian societies in the Amazon, challenging long-held assumptions about ancient populations in the region.

"The cultures and societies that composed the Aquiry shared a common worldview and constructed ceremonial centers in a variety of monumental geometric forms, characterized by deep ditches and high outer embankments, commonly known as Amazonian geoglyphs," Martti Pärssinen, an archaeologist at the University of Helsinki, told Live Science.

In a new study published on July 29 in the journal Nature, Pärssinen and his team revealed the results of a survey covering nearly 1,740 square miles (4,500 square kilometres) of rainforest.

The research uncovered 396 previously unknown geoglyphs and helped scientists estimate the likely extent of the Aquiry civilisation.

Pärssinen has studied geometric earthworks in Brazil’s Acre state for more than 20 years. In 2021, he formally introduced the name Aquiry for the ancient multicultural society, taking the name from the Acre River, which runs from Peru and Bolivia through modern-day Acre and Amazonas in Brazil.

The word Aquiry means "river of caimans" in the language of the Indigenous Arawakan people.

The legend of El Dorado—meaning "the gilded one" in Spanish—originated from a ritual where a native Muisca chieftain covered himself in gold dust and dove into a sacred lake.

Spanish conquistadors misunderstood this ceremony, falsely believing El Dorado was a literal empire built entirely out of solid gold and hidden deep within South America.

This obsession triggered centuries of dangerous and destructive European expeditions into the Amazon, forever altering history in the pursuit of wealth that never actually existed.

Because thick rainforest vegetation hides much of the archaeological record, modern day researchers have relied heavily on lidar and airborne laser scanning technology to identify the remains of the civilisation.

The geoglyphs were built between 600 B.C. and A.D. 850, according to the study. The people who created them lived in large family longhouses near the earthworks and cultivated crops including maize and squash.

"According to native oral traditions, the Aquiry centers were built to foster relations among communities" and with important otherworldly beings, Pärssinen said.

He added that the sites also acted as places for gatherings, political decision-making and displays of generosity by local leaders.

Archaeologists have so far identified around 1,700 geoglyphs in the region, but researchers believe the true number could be far greater.

They estimate more than 20,000 Aquiry earthworks may still be waiting to be discovered in unexplored areas. Based on an estimate that around 300 people were needed to construct and maintain each geoglyph, the researchers calculated that the civilisation may have reached a peak population of between 1.25 million and 3 million people between A.D. 100 and 300.

M. Pärssinen & F. de Novaes

Scientists have uncovered evidence of a real lost civilisation beneath the Amazon rainforest (Image: M. Pärssinen & F. de Novaes)

The discoveries have drawn comparisons with the famous Nazca Lines of Peru, another collection of ancient geoglyphs created between 200 B.C. and A.D. 500.

However, Pärssinen said the two cultures were likely separate.

"The Nazca geoglyphs represent a different phenomenon and were probably unrelated to the Aquiry civilization," he said.

"Nevertheless, in both cases, the straight roads and lines, as well as the geometric forms and motifs, are best appreciated from the air."

The growing evidence of extensive ancient settlement in the southwest Amazon is forcing archaeologists to reconsider ideas about pre-Columbian societies and urban development.

But one major mystery remains: what caused the Aquiry civilisation to disappear?

"We do not know why the geoglyphs were suddenly abandoned between A.D. 850 and 950," Pärssinen said.

"The available evidence points to a relatively rapid collapse" that may have coincided with the decline of other major pre-Columbian societies, he added, including "the Classic Maya in Central America and the Tiwanaku and Wari civilizations in the Andes."