In recent years, the use of drones has allowed archaeologists to uncover some of the world’s most interesting history and hidden secrets. In 2017, for example, the technology helped them map 2,000-year-old Venezuelan rock carvings.

Now, with the use of drones, archaeologists in Peru have uncovered more than 50 new examples of Nazca lines in the Palpa province that likely would have been missed by the human eye and even satellites, reports Michael Greshko in a National Geographic exclusive on the discovery.

Unesco has called Nazca lines one of the “greatest enigmas” of archaeology. The works are created by moving stones to remove a top layer of soil and reveal lighter colored soil underneath, and more than a thousand of these ancient geoglyphs populate a 290 square mile span of the Nazca Desert in southern Peru. While researchers have known about the lines—which depict plants, creatures and geometric designs—since the 1920s, they first started studying them from the sky in the 1940s.

Most of the newly found lines were created by the Nazca culture, which existed from between 200 to 700 C.E. But researchers believer that earlier civilizations, the Paracas and Topará cultures, carved some of the lines between 500 B.C. and 200 C.E.

The new findings come as a result of a grant given to the country after Greenpeace protesters damaged Nazca lines, Eli Rosenberg reports for The Washington Post.

According to National Geographic, the analysis of satellite images was crowdsourced to volunteers using archaeologist Sarah Parcak’s GlobalXplorer initiative, which looks for signs of looting or unknown archaeological sites. Researchers then visited the location and found decades-old signs of looting and trespassing spurred by the area’s booming illegal gold mines.

But after imaging the site with drones, they discovered something remarkable: 50 or so ancient Nazca lines that had been hiding in plain sight, Greshko reports. As Michelle Starr reports for ScienceAlert, the lines hadn’t before been spotted because of degradation and erosion. But drones have allowed researchers to find even the faintest signs of the geoglyphs. At altitudes of 200 or less, drones can see objects less than half an inch wide.

“Most of these figures are warriors,” co-discoverer of the new lines, Peruvian archaeologist Luis Jaime Castillo Butters tells Greshko. “These ones could be spotted from a certain distance, so people had seen them, but over time, they were completely erased.”

The new discovery highlights important context around the transition of the Paracas and the Nasca. “This means that it is a tradition of over a thousand years that precedes the famous geoglyphs of the Nazca culture, which opens the door to new hypotheses about its function and meaning,” Peruvian Ministry of Culture archaeologist Johny Isla, who is Nazca lines’ chief restorer, tells Greshko.

Last year, Isla also identified a previously unidentified orca geoglyph in the same region.

"[This discovery] is really quite exciting," Charles Stanish of University of South Florida tells LiveScience’s Laura Geggel. Stanish, who was not involved in the research, visited the site last week. "I've been working there for 30-some years, so it was fun to see something new,” he says.

While researchers know how the lines were made, they still haven’t quite figured out why they were created. The new discovery might lead to a better understanding of their purpose, National Geographic's Kristin Romey tells Ryan F. Mandelbaum of Gizmodo.

Now that the lines are known, the researchers' next step is to look into protecting the glyphs. While the discovery falls within the Unesco World Heritage Site's boundaries, the lines have not yet been registered with the Peruvian Ministry of Culture. Maps and drawings needed for that designation are already underway. They’re also hoping to protect the lines from the bigger threat: human encroachment, ScienceAlert reports.

In the meantime, keep your eyes peeled for new discoveries on the horizon—Mandelbaum reports that researchers are continuing their survey of the area through GlobalXplorer.