Durable Designs: Hundreds more Nazca lines emerge in Peru’s desert

FRANZ LIDZ

Gouged into a barren stretch of pampa in southern Peru, the Nazca Lines are one of archaeology’s most perplexing mysteries. On the floor of the coastal desert, the shallow markings look like simple furrows. But from the air, hundreds of feet up, they morph into trapezoids, spirals and zigzags in some locations, and stylized hummingbirds and spiders in others. There is even a cat with the tail of a fish. Thousands of lines jump cliffs and traverse ravines without changing course; the longest is bullet-straight and extends for more than 15 miles.

The vast incisions were brought to the world’s attention in the mid-1920s by a Peruvian scientist who spotted them while hiking through the Nazca foothills. Over the next decade, commercial pilots passing over the region revealed the enormousness of the artwork, which is believed to have been created from 200 BC to 700 AD by a civilization that predated the Inca.

“It took nearly a century to discover a total of 430 figurative geoglyphs,” said Masato Sakai, an archaeologist at Yamagata University in Japan who has studied the lines for 30 years. Sakai is the lead author of a survey published in September in the Proceedings of the National Academy of Sciences that found 303 previously uncharted geoglyphs in only six months, almost doubling the number that had been mapped as of 2020. The researchers used artificial intelligence in tandem with low-flying drones that covered some 243 square miles. Their conclusions also provided insights into the symbols’ enigmatic purpose.

The newly found images — an average of 30 feet across — could have been detected in past flyovers if the pilots had known where to look. But the pampa is so immense that “finding the needle in the haystack becomes practically impossible without the help of automation,” said Marcus Freitag, an IBM physicist who collaborated on the project.

To identify the new geoglyphs, which are smaller than earlier examples, the investigators used an application capable of discerning the outlines from aerial photographs, no matter how faint. “The AI was able to eliminate 98% of the imagery,” Freitag said. “Human experts now only need to confirm or reject plausible candidates.”

That 2% flagged by AI amounted to 47,410 potential sites from the desert plain. Sakai’s team then pored over the high-resolution photos and narrowed the field to 1,309 candidates. “These were then categorised into three groups based on their potential, allowing us to predict their likelihood of being actual geoglyphs before visiting,” Sakai said. Two years ago, the researchers started scouting the more promising locations by foot and with drones, ultimately “ground-truthing” 303 geoglyphs. Among the depictions were plants, people, snakes, monkeys, cats, parrots, llamas and a grisly tableau of a knife-wielding orca severing a human head. Of the new figures, 244 were suggested by the technology, while the other 59 were identified during the fieldwork unaided by AI.

The Nazca people carved the designs into the earth by scraping back the pebbled, rust-coloured surface to expose the yellow-gray subsoil. Little is known about the shadowy culture, which left no written record. Aside from the etchings, pretty much all that exists of the civilization are pieces of pottery and an ingenious, still functioning irrigation network.

Of the original 1,309 candidates, Sakai estimates there are at least another 500 undetected figures. “I expect that more surprising facts will emerge,” he said.