NatGeo Adventure has posted a great piece on a pair of climbers helping archaeologists explore high-perched caves in the Mustang region of northern Nepal. Locals say they’ve seen old manuscripts fluttering out of one of the caves, but the altitude and nature of the rock made the task too daunting for anyone but the best to venture up.

“The challenges were daunting,” says Peter Athans, aka “Mr. Everest,” of scaling a set of crumbling cliffs—more mud than rock—for the benefit of science. “At times we were climbing what looked like overhanging drip sand castles. We’d kick at a feature that we thought was a massive boulder, only to watch it collapse and fall in a cloud of sand and dust.”

With special permission from the Nepalese government, Athans and climber Renan Ozturk fixed three-foot-long anchors deep into the crumbling walls. The going was slow: At one point, it took 14 hours to cover 328 feet. The duo eventually reached a series of tunnels and shafts, fixing a route inside the cliffs while dodging rockfall. “It was like climbing through a dust storm,” Ozturk says. After working their way to the top of the complex, the climbers traversed from one opening to the next and soon entered a large domed room littered with more than 8,000 ancient manuscript folios, the illuminated pages filled with images of pre-Buddhist Bön deities. “It was the first time in my career that I got to use climbing techniques for something other than mountaineering,” Athans says.

After the climbers lowered the manuscripts in rucksacks, at which point nearby monks did an initial cleaning, anthropologist Charles Ramble of Oxford determined that they date back to the 15th century. It looks like the region’s first kings actually practiced Bön, not just Buddhism, which is an unsettling discovery for the locals, who tend to consider Bön to be a primitive religion full of black magic.

Either way, hats off to the climbers, whose expertise was clearly essential in this impressive “rescue” mission.