July 28, 2025
High above the arid cliffs and canyons of Upper Mustang, hundreds of man-made caves cling to vertical rock faces like forgotten doorways into time. These Sky Caves, carved into sandstone cliffs thousands of years ago, remain one of Nepal’s greatest archaeological mysteries.
Who built them? Why were they used? And what secrets still lie inside?
Let’s journey through Mustang’s ghostly cave complexes — a landscape that blends the raw drama of geology with layers of history, ancient art, and sacred ritual.
What Are the Sky Caves?
The Sky Caves of Mustang (sometimes referred to as the “Lo Manthang Caves” or “Chhoser Caves”) are an intricate network of over 10,000 man-made caves carved into sheer rock faces, often more than 50 meters above the valley floor.
Some are single chambers, while others span multi-story labyrinths connected by tunnels, wooden ladders, and vertical shafts. Many are now inaccessible, eroded by centuries of wind and isolation.
Where Are They?
The most prominent cave complexes are located near Chhoser village, just north of Lo Manthang, the ancient capital of the Mustang Kingdom. Others are scattered along the Kali Gandaki River gorge, the deepest in the world.
You’ll see:
- Jhong Cave (Chhoser) – A popular 5-story structure open to visitors
- Yara and Ghara caves – Believed to have served as monasteries or meditation retreats
- Tangbe and Tetang – Sites with burial caves and ancient bones
How Old Are They?
Carbon dating and research suggest that some caves may be as old as 3,000 years, though widespread use likely peaked between the 10th and 14th centuries CE.
They served different purposes across different eras:
- Prehistoric shelters and burial sites
- Monastic retreats during the rise of Tibetan Buddhism
- Refuges during periods of conflict in Mustang’s medieval past
Ritual Use and the Afterlife
In the early periods, many caves were used for sky burials and secondary burials, reflecting beliefs in the impermanence of the body and the recycling of spiritual energy. Human remains, including partially defleshed bones, have been discovered in ossuary caves.
Some caves contain mummified bodies, sacred texts written in Tibetan, murals of Bodhisattvas, and meditation niches — pointing to deep religious use.
The Discovery That Shocked Archaeologists
In 2007–2010, an expedition led by Cory Richards (photographer) and Pete Athans (mountaineer) documented newly opened caves with the help of local knowledge and climbing gear.
They found:
- Ancient Buddhist paintings, some dating to the 12th century, with scenes of demons, Buddhas, and tantric rituals
- Manuscripts written in ancient Tibetan script
- Burial chambers containing human bones arranged in ceremonial positions
- Mysterious artifacts including chess-like pieces, scrolls, and masks
These findings suggest the caves were once religious centers, libraries, and hidden sanctuaries in times of invasion.
The Sky Caves in Mustang’s Oral History
According to local folklore:
- Some caves were built by Lo Gyelbu, a legendary king said to have superhuman abilities.
- Others are believed to have been inhabited by meditating lamas who achieved siddhi (spiritual perfection).
- One tale tells of a demoness who once lived in the cliffs of Chhoser, tamed by a saint using mantras and thunderbolts.
Even today, locals may hesitate to enter certain caves — believing they house lingering spirits or hold powers best left undisturbed.
The Sky Caves and Filmmakers
These caves have fascinated documentary filmmakers and archaeologists alike:
- National Geographic has featured the Mustang caves in its “Lost Caves of Tibet” special.
- The visual drama — ochre cliffs, hidden entrances, interiors lit by torchlight — offers a cinematic landscape like no other in the Himalayas.
- Yet, due to their cultural and environmental sensitivity, filming may require special permits from the Department of Archaeology and Upper Mustang authorities.
Visiting the Sky Caves: Practical Tips
- Permit: You’ll need the Restricted Area Permit for Upper Mustang, and must travel with a licensed guide.
- Accessibility: The Jhong Cave in Chhoser is open to visitors and has ladders and stairs inside.
- Best Time to Visit: Spring (Apr–Jun) and Autumn (Sep–Nov)
- Be Respectful: Many caves are sacred. Some are closed to the public to prevent further degradation.
Hanging high above the valleys of Upper Mustang, the Sky Caves are more than archaeological sites — they’re doorways into a forgotten world where belief, art, and survival were etched into stone. Their mystery lingers still, calling out to explorers, scholars, and seekers of lost stories.