- An estimated 10,000 of the caves have been found in the former Kingdom of Mustang in North, Central Nepal
- They have either been dug into the cliffside or tunnelled from above
- Caves are thousands of years old but who built them and why remains a mystery
Thousands of holes are carved into the fragile, sandy-coloured cliff in a gorge so large it dwarfs the Grand Canyon.
The astonishing number of caves, some dug into the cliffside, others tunnelled from above are thousands of years old but who built them and why remains a mystery.
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Mystery: Thousands of man-made caves 155ft from the ground lie hidden within the Himilayas in a gorge so large it dwarfs the Grand Canyon
Bizarre: With dozens of holes carved into the fragile, sandy-coloured cliff face this unusual 'neighbourhood in the sky' looks like a giant sandcastle
Dangerous: Climber Cedar Wright explores the series of caves near the village of Tsele
It is also not known how people climbed into the caves which are dug into a cliff 155-foot above the valley floor.
An estimated 10,000 of these mysterious human-built caves have been found in the former Kingdom of Mustang in North, Central Nepal. Those who have seen the mysterious caves say the effect of them on the cliff face makes it look like a giant sandcastle.
Adventure photographer, Cory Richards joined climber Pete Athans, archaeologist Mark Aldenderfer and a team of explorers to unearth the hidden relics of the ancient and remote caves.
Mr Richards said: 'I was in Nepal working in this village called Forte, where Pete [Athans] and I were teaching a group of Sherpas climbing techniques, safe climbing techniques so they could climb Everest.
'And Pete asked me if I would be interested in this project in Mustang.