Lidar allowed researchers to penetrate thick jungle vegetation. The technology works by emitting laser pulses (from an aircraft) that travel to the Earth's surface and bounce back, creating detailed 3D maps of the terrain below.

The Amazon was widely perceived as a wilderness, inhabited by small, disparate groups. This area was thought to be incapable of harbouring intricate, interconnected communities. The dense forest canopy also concealed evidence of large-scale human settlement and modification of the landscape. This new discovery, however, which builds on earlier discoveries of earthen mounds and concealed roads, shatters our previously-held notions about the region.

The discovered cities, inhabited from around 500 BCE to between 300 and 600 CE, demonstrate a level of urban planning and environmental management that challenges previous notions of Amazon cultures. Of note are the extensive roads, which indicate a well-organised and stratified society with a division of labour.

The scale and complexity of these settlements are thought to rival those of famed ancient civilizations, such as the Mayan civilization in Central America. Speaking to The Associated Press, lead archaeologist Stéphen Rostain noted that "It was a lost valley of cities."

These extensive settlements, spanning roughly 115 square miles, were home to sophisticated urban centres with over 6,000 earthen platforms, intricate road systems, plazas, terraces, and agricultural fields. Archaeologists believe this connected network of settlements housed 10,000 or more farmers. This network of settlements may have been inhabited for roughly 1,000 years.

Learning about our farming ancestors…

In the past decade alone, Lidar has helped unearth ancient Mayan civilizations in Guatemala and Olmec ruins in Mexico. In these regions, the technology uncovered extensive, previously unknown settlements, including pyramids, palaces, and entire cities.

Lidar does more than uncover lost cities though. It has also been used to map ancient agricultural systems, track changes in landscape use over time, and understand the environmental impacts of historical human activities. Overall, it has become an indispensable tool in archaeology and its integration with traditional fieldwork has helped archaeologists to study and excavate civilizations in detail.

In terms of scale, the unearthed Amazon civilization stands on par with many well-known Maya and Inca urban centres found in the Americas. The Maya civilization, known for its majestic pyramids and cities like Tikal and Chichén Itzá, thrived in Central America from around 2000 BCE to the 16th century CE. The Inca Empire, famous for wonders like Machu Picchu, dominated a large portion of western South America from the early 15th century until the Spanish conquest in the 16th century.

I’ve had the privilege of visiting Chichén Itzá and Machu Picchu and can attest to their grandeur. No such spectacular monuments have been unearthed in the Upano Valley yet, but it’s worth noting that the newly discovered settlements were contemporaneous with the later periods of the Maya civilization and predated the Incan empire. Their existence for close to a millennium, spanning until about 600 CE, highlights a long-lasting, stable civilization that rivals the timelines of their more famous Central American and Andean counterparts.

...And the Amazon region

We do not know what happened to the remarkable civilization uncovered in the Upano Valley though. The precise reasons for its decline are unknown. It vanished long before the arrival of European explorers in the Americas, leaving a mystery in the jungle.

The discovery sheds light on the remarkable ingenuity of ancient communities in transforming their environment, constructing settlements, and creating agricultural systems.

Today, the legacy of these ancient communities lives on in the indigenous populations of the region, notably the Shuar and Achuar peoples. These communities, while distinct from the vanished civilization, maintain a deep connection to the land. Understanding their history and connection to the vanished civilization will provide cultural and historical context, enriching our understanding of these discoveries.

These findings can also guide contemporary discussions on conservation and sustainable land use in the Amazon. At present, there is a need to engage with the indigenous communities currently inhabiting these regions.

The authors agree noting that this “discovery is another vivid example of the underestimation of Amazonia’s twofold heritage: environmental but also cultural, and therefore Indigenous.” They emphasise the need to reevaluate ideas and interpretations of the Amazon, in a way that is inclusive and encourages participation of local communities.

Anirban Mahapatra is a scientist and author. His second popular science book, When The Drugs Don’t Work: The Hidden Pandemic That Could End Medicine, will be published this year. The views expressed are personal.