Study reveals over 400 earthen structures from the Akiri culture
On July 30, 2026, a study published in Nature documented 432 earthen structures of the Akiri civilization in southwestern Amazonia, 396 of which had never been recorded before. The Akiri existed from approximately 600 BCE to 850 CE. At their peak, they occupied up to 183,000 square kilometers and could have supported 1.2 to 3 million people. The research utilized LIDAR, a technique that fires laser pulses from an aircraft to map the ground. These findings challenge earlier assumptions that the Amazon was a sparsely populated wilderness prior to European contact.
Survey methodology
Researchers surveyed 4,497 square kilometers of forest by conducting flight lines totaling about 450 kilometers. The dataset revealed 432 earthworks, pointing to extensive construction activity by the Akiri.
'The sheer number of geoglyphs and earthworks discovered in less than 3% of the greater Amazon surprised us the most.'
- Martti Pärssinen, archaeologist-anthropologist at the University of Helsinki
Pärssinen also noted that 'the scale of the archaeological finds suggests many other Amazon regions may have been far more densely populated and heavily modified than previously thought.' He added that 'at the center of many of these clearings, large geometric earthworks would have stood, connected by wide and narrow roads.' These discoveries open new perspectives for studying the history and development of Amazonian civilizations that were previously little known.
The identification of new Akiri earthworks highlights the importance of modern tools like LIDAR in archaeology. This research could reshape our understanding of population density and social organization in ancient Amazonian societies, offering fresh opportunities for investigation. The geoglyphs and architectural features are likely to become a foundation for deeper study of Akiri cultural and economic life, as well as their environmental influence.