Sky Caves of Mustang: The 10,000 Ancient Cliff Caves of Nepal

The Sky Caves of Mustang, also called the Mustang Caves or the mysterious caves of Mustang, are a vast collection of human-made cavities carved into the sheer, wind-eroded cliffs of Upper Mustang in north-central Nepal. Researchers estimate there are around 10,000 of them, hollowed out of the soft sandstone and conglomerate walls that line the Kali Gandaki river gorge and its side valleys. Many sit dozens of metres above the valley floor, some as high as 40 to 50 metres, reachable today only with ropes and climbing gear.

The caves form one of the world's great archaeological puzzles. No written record explains who dug them, exactly when, or how people climbed to them, since the original access ladders, ledges and staircases have largely eroded away. What survives is the honeycombed cliff face itself, often stacked several storeys high, dotted with square window-like openings that give the whole formation its eerie, apartment-block appearance.

Upper Mustang was, until 1992, closed to outsiders, and it remains a restricted area of Nepal. That long isolation helped preserve the caves and the artefacts inside them, but also meant systematic study began late. Serious scientific investigation only gathered pace from the 1990s onward, led by joint Nepali and international teams working with Nepal's Department of Archaeology.

Age estimates come from radiocarbon dating of human remains and objects found inside the caves, so the figures below are researcher estimates rather than fixed dates. In the mid-1990s, a Nepali–German team (with the University of Cologne) recovered several dozen partially mummified bodies from Mustang caves that were dated to at least around 2,000 years old. Later work pushed the human story back further, with genetic evidence suggesting the ancestors of these cave communities had moved onto the Tibetan plateau as early as roughly 3,000 years ago.

Archaeologists led by Mark Aldenderfer, working with climber Pete Athans and Nepali colleagues, carried out a series of expeditions from the late 2000s. Their most famous work was at Samdzong, a cluster of shaft tombs cut into a cliff at about 4,000 metres. Since 2010 the Samdzong tombs have yielded the remains of more than a hundred individuals, with the burials broadly dated to between the 3rd and 8th centuries CE.

Scholars generally describe three overlapping phases of use for the caves. The earliest phase, from roughly 1,000 BCE, appears to have been for burials. A later phase, around the 10th century CE, saw caves used as fortified dwellings during periods of conflict. By the medieval era (roughly the 13th to 15th centuries), some caves and cave complexes were adapted as Buddhist meditation retreats, shrines and monasteries. Exactly how the earliest people reached and excavated caves so high on the cliffs remains unknown.

The Samdzong tombs produced some of Nepal's most striking archaeological discoveries. Tomb Samdzong 5 contained a gold-and-silver funerary mask, along with copper vessels, iron daggers, glass and stone beads, and textiles. Analysis of the metals suggested much of the raw material had a South Asian origin, while the styles pointed to contacts with Central Asia and the Silk Road trade network. The cloth from that tomb was dated to roughly 400–650 CE, and the find was popularised by National Geographic, which featured the mask and burial in its coverage in 2012.

The human remains themselves have told researchers a great deal. Skeletons from Samdzong showed clear cut-marks made around the time of death, which specialists interpret as evidence that bodies were defleshed before burial rather than buried whole. Investigators reported no signs of deliberate artificial mummification at Samdzong; the partial mummification seen at some other Mustang caves is thought to result from the cold, dry, high-altitude conditions.

Alongside the ancient burials, later expeditions found rich Buddhist material. In 2007, a US–Italian–Nepali team documented cave murals, manuscripts and pottery dated to around the 13th century. A follow-up expedition in 2008 recovered further human remains and illuminated manuscripts blending Buddhist and Bon religious writing. Together these finds show the caves were reused across many centuries and belief systems, from the pre-Buddhist Bon tradition to later Tibetan Buddhism.

The most-visited of the sky caves is the Chhoser cave, widely known as the Jhong cave (also written Shija Jhong), located in Chhoser village around 9 kilometres north of the walled town of Lo Manthang. Unlike the sealed burial tombs, this is a walkable multi-storey cave complex, making it the easiest place for ordinary visitors to experience a Mustang cave from the inside.

Standing close to 50 metres tall, the Jhong cave contains dozens of interconnected chambers spread over five levels, joined by carved passages, ledges and ladders. The rooms are thought to have served as living quarters, storage spaces, kitchens with smoke-blackened ceilings, meditation cells and lookout or defence positions. Local tradition and researchers estimate the complex is well over 2,000 years old, and it is often cited as one of the oldest man-made structures in the Himalaya.

Over the centuries the cave is said to have sheltered local families and, more recently, been associated with periods of unrest such as the Khampa resistance based in Mustang in the mid-20th century. For visitors interested in the '10,000 caves of Nepal' story, Chhoser offers the clearest, safest window into how these vertical settlements once worked.

Some Mustang caves were transformed into remarkable Buddhist sanctuaries. The best known is Luri Gompa, a cave monastery built into a cliff near the villages of Yara and Ghara in the southern part of Upper Mustang. Its inner chorten cave is decorated with well-preserved murals, and art historians such as Mary Slusser and Helmut Neumann have dated the temple to around the 13th–14th centuries. Luri is regarded as one of the finest surviving examples of early cave-temple painting in the Nepalese Himalaya.

A short walk away lies Tashi Kabum, a related cave temple first brought to scholarly attention by the American guide Gary McCue in 1992. Tashi Kabum forms part of a small group of caves cut about 50 metres above the valley floor. At its heart is a chorten (a Buddhist reliquary monument) surrounded by space for ritual circumambulation, set beneath a domed ceiling painted with a mandala.

The Tashi Kabum murals are unusual within Mustang, worked in flat earthen and ochre tones, and feature the Shadakshari Lokeshvara — a form of Avalokiteshvara (Chenresik) named for the six-syllable mantra 'om mani padme hum', which is also inscribed on the wall. The upper part of the chorten was damaged by robbers, but the ceiling and wall paintings survive. Scholars link the styles of Luri and Tashi Kabum closely, both to each other and to the wider tradition of early western-Himalayan Buddhist art.

Upper Mustang is a designated restricted area, so foreign travellers need a Restricted Area Permit (RAP) in addition to the Annapurna Conservation Area Project (ACAP) permit. The RAP cannot be obtained by individuals directly: it must be arranged through a Nepal government–registered trekking agency, and the rules require a minimum of two foreign trekkers travelling together with a licensed guide. Trekking or driving into the area without the permit is illegal and can lead to heavy fines and deportation.

The fee structure changed substantially at the end of 2025. Previously the Upper Mustang RAP cost a flat USD 500 per person for the first 10 days, plus USD 50 for each additional day. In November 2025 the Government of Nepal scrapped the flat USD 500 charge and the 10-day minimum, replacing it with a flexible rate of USD 50 per person per day, applied by amending the schedule of the Immigration Regulations. Travellers now pay only for the days they actually spend in the restricted zone.

The permit covers the Upper Mustang restricted zone north of Kagbeni, including Lo Manthang and surrounding rural municipalities. Because rules and fees are periodically revised, confirm the current rate and conditions with the Department of Immigration, the Nepal Tourism Board or a registered agency before you travel. Note that Chhoser, Luri Gompa and the Samdzong area all lie within this permit zone.

The Sky Caves of Mustang sit at the crossroads of the trans-Himalayan trade routes that once linked the Indian plains with Tibet and Central Asia along the Kali Gandaki corridor. The Silk Road connections revealed by the Samdzong finds — imported textiles, metals and burial customs — show that this remote valley was far from isolated in ancient times, and help explain how ideas, goods and beliefs moved across the high Himalaya.

The caves are also fragile. Erosion constantly eats away at the cliffs, and looting has damaged tombs and stripped murals. Mustang has been on Nepal's UNESCO World Heritage tentative list since 1996, and local institutions such as the museum at Lo Manthang display beads, bones, pendants and other recovered objects to help interpret and protect the heritage.

For visitors and researchers alike, the sky caves remain an open question. Much of the cliff-face honeycomb has never been surveyed, and each expedition tends to raise as many puzzles as it solves — above all, how a small high-altitude population carved, climbed to and used tens of thousands of caves over three thousand years. That enduring mystery is a large part of why 'the mysterious caves of Mustang' continue to draw archaeologists and travellers from around the world.