In the Peruvian desert, hundreds of ancient drawings featuring decapitated human heads and domesticated llamas have been unveiled with the assistance of artificial intelligence. Archaeologists have previously associated these artworks with the Nazca culture, which began etching these geoglyphs into the earth approximately 2000 years ago. These newly uncovered geoglyphs are not only smaller but also older than the well-known Nazca lines and other figures previously discovered, which depict enormous geometric designs stretching several kilometers or wild animals averaging around 90 meters in length. In contrast, the newly identified images generally portray humanoid figures and domesticated animals measuring about 9 meters long. Some depictions even suggest themes of human sacrifice, illustrating decapitated heads alongside killer whales wielding blades. “Certain pottery from the Nazca period showcases scenes of orcas using knives to sever human heads, ” explains Masato Sakai from Yamagata University in Japan. “This positions orcas as entities involved in human sacrifice. ” Sakai and his team identified these smaller geoglyphs by training an AI model to detect them in aerial images. These high-resolution photos spanned an area roughly ten times larger than Manhattan, covering the Nazca Pampa desert plateau and its vicinity, an area designated as a UNESCO World Heritage Site for the Nazca lines. The AI generated a gridded map indicating the likelihood of geoglyph presence within each grid square. Researchers still dedicated over 2, 600 hours to manually examine the most promising photos and conduct field inspections at the locations.

However, they estimate that the AI accelerated the screening process by a factor of 50 “by filtering out 98 percent of low-probability aerial images and providing probabilities for the remaining 2 percent, ” remarks co-author Marcus Freitag from IBM Research in New York. Acting on the AI's recommendations, the researchers uncovered a total of 303 figurative geoglyphs during field surveys conducted in 2022 and 2023. Among these, 178 were independently identified by the AI, while another 66 were not specifically marked but were found within groups of geoglyphs highlighted by the AI. “The AI-guided assessment of remote sensing data marks a significant advancement, as a complete map of the Nazca region's geoglyphs is still unavailable, ” states Karsten Lambers from Leiden University in the Netherlands. Nonetheless, he cautioned that “this advanced technology is likely to detect more visible geoglyphs—essentially the 'low-hanging fruit'—rather than the harder-to-find ones that still remain undiscovered. ” Approximately 1, 000 AI-identified candidates are awaiting evaluation in future field surveys, Sakai notes. These smaller geoglyphs typically appear on hillsides along winding trails and likely played a role in the ritual activities of individuals or small groups. Conversely, the monumental line geoglyphs likely served as focal points for communal rituals, he adds. The AI-driven screening process also shows potential for uncovering geoglyphs in areas beyond the current borders of the Nazca lines World Heritage Site, asserts David Beresford-Jones from the University of Cambridge. The urgency is paramount, as many geoglyphs “stand on the brink of destruction due to agricultural expansion, urban development, and wind-power initiatives, ” he notes.