The oldest-known evidence of humans living at extremely high altitudes has been discovered in the Peruvian Andes.

The sites, an open-air workshop with stone tools and fragments and a rock shelter with traces of Ice Age campfires and rock art, are located nearly 14,700 feet above sea level and were occupied 12,000 years ago, according to Live Science.

A team of archaeologists lead by Kurt Rademaker, a researcher at Germany's University of Tubingen, were compelled to search the Peruvian Andes after stumbling upon obsidian, a glass-like volcanic rock that they knew could have only been carried from the coast by humans.

The findings also raised questions regarding how these settlers adapted to sky-high living.

"Either they genetically adapted really, really fast within 2,000 years to be able to settle this area, or genetic adaptation isn't necessary at all," said Rademaker, the lead study author, who was a University of Maine visiting assistant professor in anthropology when he conducted the study, according to a press release.

The discovery was outlined in a paper published Friday in the journal Science Magazine.

It also suggests that ancient people in South America were living at extremely high altitudes 2,000 years after humans first reached the continent.

"Human colonization of the Americas was the most rapid and extensive geographic expansion in our species' history, in which hunter-gatherers successfully settled some of the most challenging environments on Earth," Rademaker said in a press release. "The fact that hunter-gatherers were physiologically capable of living in high-altitude mountains at the end of an ice age is an example of how amazingly adaptable our species is."

The team plans to look for more evidence of occupation, like human remains, in follow-up work.

Bones collected from the settlements could mean the dwellers there hunted and ate llama-like creatures called vicuna and guanaco, according to the release. They also killed and ate deer-like animals called tarucas.

Researchers believe there would have been unique resource opportunities so high up, like new animals to hunt and a lot more water than the nearby Atacama Desert.

"For me, a mountain lover, it's inconceivable to think that people wouldn't have popped on up there to avail themselves of the unique resources in that environment at the first opportunity," Bonnie Pitblado, an anthropologist at the University of Oklahoma who wasn't involved in the study, said to Newsweek. 

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