Set against a stunning Himalayan backdrop, this high-altitude hike is one of the best ways to experience one of Asia’s oldest religions and search for one of its most elusive animals.

Khenpo Nyima Samdrup, the abbot of Thasung Tholing Gompa in Nepal, sat in front of a stove in the monastery’s tiny kitchen, dressed in layers of maroon robes and a woolen mustard hat. The day I visited, the surrounding mountains were hidden behind thick clouds, and the wind skimmed across the lake from the north, bringing small ripples to its surface. As he fed the fire with more wood, Khenpo explained that the monastery was founded around 400 years ago to protect snow leopards, musk deer, and other animals from hunters. “Tha means ‘surrounding,’ and sung means ‘conservation’ or ‘protection,'” he explained. “So, the monastery’s name means ‘preserving the surroundings.'”

Thasung Tsholing is a monastery of the ancient Bon religion set on the edge of Phoksundo Lake in Dolpo, northwest Nepal. The remote Dolpo region is culturally Tibetan, a rugged land of jagged gorges, high passes, and secluded religious hermitages. It is one of the last vestiges of Bon – the indigenous religion practiced across the Tibetan plateau before the arrival of Buddhism in the 7th Century CE. The monastery also lies on the Lower Dolpo Circuit – a 220km trekking trail that winds through the southerly reaches of Dolpo.

Following the destruction of Bon and other religious sites in Tibet during the Cultural Revolution in the 1960s and ’70s, in which the Chinese government attempted to eradicate Tibet’s cultural and spiritual identity, Chinese forces sought to assimilate Tibetans forcibly. But because Dolpo lies just over the border in Nepal, it is one of the very few places where the practice of Bon has continued uninterrupted for centuries. Today, only 0.23% of Nepalis are Bon, with most of the population following the Hindu religion.

The Circuit connects four of the area’s six main Bon settlements, providing an unparalleled opportunity for hikers to discover this mysterious religion. A registered guide is required to trek in the region, and they can arrange for hikers to stay with Bon families, visit ancient Bon monasteries, meet local religious leaders, and observe the slow, gentle rhythms of Bon culture – most notably, the reverence of their natural environment. Bon followers consider certain animals and elements – such as mountains, rocks, rivers, canyons, and springs – gods or protectors and believe their destruction will bring great misfortune to humanity. Humans must, therefore, ask permission from these gods before beginning any activity that uses the land’s natural resources – such as picking medicinal plants, quarrying for stone, or planting seeds. Such beliefs, Bon followers say, encourage respectful and sustainable use of the surrounding environment. This concept felt particularly poignant to me in an age of environmental destruction. I traveled to Dolpo to see what lessons this ancient religious practice could hold for the modern world.

The Circuit starts at the ramshackle town of Dunai, a grueling 36-hour bus journey northwest of Kathmandu. Accompanied by my Nepali trekking guide, Rejina Tamang, I followed the dusty trail eastwards, climbing past stone villages perched precariously on the valley side. The trail continued, rising and falling; the steps cut into red cliffsides high above the silver meander of the Bheri River. The Bon communities of Dolpo are agro-pastoralists – rearing goats, sheep, dzo, and yak and growing a limited range of crops. It was September and almost harvest season; the golden barley glistened in the soft autumn wind.

Tamang and I set out each morning at sunrise, covering anywhere from 10 to 25km, depending on incline and altitude. During our 14-day trek, we slept in a mixture of traditional lodges in rammed-earth houses, temporary “tent-hotels” set between villages serving rice, lentils, and local liquor, and a tent I carried in my trekking backpack and two days in, the path turned northwards into a narrowing gorge before emerging 40km northeast of Dunai in the arid valley of Dho-Tarap, one of Dolpo’s leading centers. Most of Dho-Tarap’s Bon community lives in the valley’s eastern end in a Sipchok hamlet. Tamang and I found Sipchok’s monastery locked, but a passing local insisted on taking us to her home. Her husband, Geshe Yongden Pasang, was the Bon lama, or spiritual leader, of Dho-Tarap, and after an obligatory cup of butter tea, he happily showed us the monastery.

Sipchok Monastery is roughly 450 years old and has no electricity; the dim light from the small windows was just enough to make out the painted deities on the walls. Geshe Yongden explained that Dolpo was once part of the ancient kingdom of Zhangzhung, centered around western Tibet, which has long been associated with Bon. Zhangzhung ended in the 7th Century CE when the Yarlung, the first Central Tibetan dynasty, conquered it. When the Yarlung chose Buddhism as the state religion, many followers of Bon hid their religious scriptures in the caves of holy mountains for safekeeping. They fled to outer-lying Tibetan regions such as Dolpo. Little is known about the practice of Bon in those early centuries, but today, Bon shares many beliefs – such as karma, reincarnation, and the pursuit of enlightenment – with Tibetan Buddhism. But as Geshe Yongden told me, the Bon have their deities, rituals, and a distinct origin story.

He explained that mountains are significant deities for the Bon, with the most prominent mountain in a valley being the Yulha, or “God of the place.” “If we make the Yulha angry, the rain will not fall on time, diseases will spread, crops will not grow, the snow leopard will cause more damage to the livestock, and there will be conflicts between people. But if we worship the Yulha properly, it will rain on time, the crops will grow well, people will have happy minds, and the village will be peaceful,” he said.

With lousy weather ominously approaching, we hiked 30km eastwards from Dho-Tarap towards Numa La, the first of two more-than-5000m passes on this part of the trail. We were now accompanied by Tenzin, a local horseman who knew the land, who delivered us safely across these sacred mountains to Thasung Tsholing Gompa. When we arrived at Ringmo, the Bon village next to Thasung Tsholing Gompa, huge raindrops lashed down from dark clouds. Only when we passed the chortens, or shrines, on the outskirts of the village did Tenzin allow us to stop and rest. He explained that these shrines mark the boundaries of each town and the threshold between the inhabited, safe areas and the wild domains of the gods.

The monastery sat on an area of flat land jutting out into the lake, where the only sounds were the rustle of tree branches and the tweeting of birds. However, Khenpo later explained this peaceful scene wasn’t always so. Before the monastery was built, this area was used as a trap for snow leopards and other endangered animals, such as blue and musk deer. Hunters used dogs to drive the animals towards the monastery, trapping them on the rocky outcrop extending into the lake.

“In the 17th Century, Treton Tshewang Tshultrim, an important Bon lama, came to the area and saw the hunters killing the animals. That’s why he founded this monastery, which is where it is today,” Khenpo said. Hunters would not hunt near a Bon monastery, and its presence created a deterrent that remains today. “The precepts of our religion tell us that animals should be respected, and protecting them will help accumulate karmic merit,” he added.