Archaeologists in Peru have made a groundbreaking discovery, uncovering 303 previously unknown giant symbols carved into the Nazca Desert, aided by artificial intelligence. This revelation, detailed in a study published in the journal PNAS, nearly doubles the number of known Nazca geoglyphs—mysterious artworks created by moving stones or gravel that date back around 2,000 years.

The newly identified carvings feature a variety of designs, including birds, plants, spiders, human figures with headdresses, decapitated heads, and even an orca holding a knife. These enormous symbols, located about 50 kilometers (31 miles) inland from Peru’s south coast and sitting at an elevation of 500 meters (1,640 feet), have been preserved over the centuries due to the region's dry climate and sparse population, which limits agricultural activity and flooding.

Recent advancements in remote high-resolution imaging have significantly accelerated the rate of new discoveries, with an average of 19 geoglyphs found annually between 2000 and 2020. However, the application of AI to streamline the identification process marks a significant leap forward in archaeological exploration, as noted in the study.

Led by Masato Sakai, a professor of archaeology at Japan's Yamagata University, the research team trained an object detection AI model using high-resolution imagery of the 430 Nazca symbols documented by 2020. Collaborating with researchers from IBM’s Thomas J. Watson Research Center in New York, they faced the challenge of limited training data—most AI models require tens of thousands of images for effective training.

The team focused on the smaller, more intricate figurative symbols, which measure approximately 9 meters (30 feet) in length and are harder to spot than the larger, line-type geoglyphs, which can reach up to 90 meters (98 yards). Although the AI model generated over 47,000 potential sites across the 629 square kilometers (243 square miles) of desert, the researchers filtered these suggestions, ultimately identifying 1,309 locations with high potential. Impressively, for every 36 AI suggestions, the team found one promising candidate.

Between September 2022 and February 2023, the researchers conducted field surveys of the identified sites on foot and with drones, resulting in the successful verification of 303 figurative geoglyphs. Of these, 178 were suggested by the AI model, while 125 were additional discoveries made during the fieldwork. Notably, 66 were located within AI-identified clusters, and 59 were found independently of AI assistance.

Despite the success, there are still many more geoglyphs to be uncovered. The team was unable to survey 968 promising candidates during their fieldwork, and estimates suggest that at least 248 additional figurative geoglyphs may still be waiting to be discovered.

The significance of doubling the known geoglyphs is profound, especially considering the limited training data, according to Amina Jambajantsan, a researcher at the Max Planck Institute of Geoanthropology. While she noted that AI holds great promise for archaeology, she also emphasized the continued importance of human expertise in interpreting findings.

The purpose of the Nazca symbols remains elusive, with hypotheses suggesting they may have served as sacred spaces, pilgrimage routes, or tools for calendars, astronomy, or communication. An analysis of the new and existing symbols revealed trends, showing that larger geoglyphs often depict wildlife while smaller ones frequently feature human-related imagery.

The research also illuminated a network of ancient paths in the desert, suggesting that smaller geoglyphs were strategically placed along trails used by the Nazca people to observe the symbols in groups. The larger symbols appeared near networks of straight lines, squares, and trapezoids, likely used for ceremonial activities.

The team plans to continue their work to decode the precise meanings of these geoglyphs and their significance, with further findings expected to be published in the future. According to Sakai, the meanings may be derived from the combinations of the geoglyphs, adding a rich layer to our understanding of Nazca culture.