The world's deepest gorge isn't the Grand Canyon, and trekkers walk its floor

By one measure the deepest gorge on Earth is in Nepal, and an ordinary trekking trail runs along its floor. The Kali Gandaki river cuts between two 8,000-metre peaks, Dhaulagiri and Annapurna I, and the drop from their summits to the water is more than 5,500 metres — about three times the depth of the Grand Canyon.

How a river ends up 5,500 metres below two 8,000-metre peaks

The river is older than the mountains. The Kali Gandaki is what geologists call an antecedent river: it was flowing along its course before India began colliding with Asia roughly 50 million years ago, and as the Himalaya rose around it, it kept cutting down at about the same pace instead of being pushed aside.

The result is a trench with an 8,000-metre wall on either side. Near Lete, where the riverbed is around 2,520 metres, Annapurna I stands 5,571 metres above the water on one side and Dhaulagiri 5,647 metres above it on the other.

Which gorge is really the deepest

It depends what you measure, and it is worth being straight about that. Measured as vertical relief — the drop from the highest adjacent summit to the river — the Kali Gandaki beats every other gorge on the planet.

Measured as continuous, walled canyon depth along a sustained stretch, Tibet’s Yarlung Tsangpo Grand Canyon, cut by the river that becomes the Brahmaputra, reaches about 6,009 metres and is usually named the deepest by that stricter definition. Both are real superlatives measuring different things.

The fossils in the riverbed

Between Damodar Kund and Kagbeni, the river washes out black, coiled fossils that Hindus and Buddhists have venerated for more than 2,000 years. They are shaligrams, the remains of ammonites — spiral-shelled sea creatures that lived in the Tethys Sea about 140 million years ago — and they are revered as a living form of Vishnu.

Walk the gorge floor near Kagbeni or Jomsom and you will see trekkers and pilgrims crouched over the grey stones, cracking them open. They are getting harder to find: shifts in the river’s course, which researchers link to a changing climate, are burying and moving the beds they come from. They are younger than the seabed at the top of Everest, from a later stage of the same ocean — why there are seashells at the top of Everest.

Walking it, and driving it

This is not a gorge you look at from a fenced overlook; it is one of Nepal’s most walked trekking corridors. The Annapurna Circuit and the Jomsom–Muktinath trek follow it upstream through Tatopani, Ghasa, Lete, Marpha and Jomsom before climbing toward Muktinath, a route pilgrims have used for centuries.

You can also drive the bottom of it: the Pokhara to Jomsom road is roughly 180 km and takes seven to nine hours, climbing from about 820 m to 2,720 m through the gorge. Either way, plan to be moving before midday — by early afternoon the gorge funnels a strong wind up through Kagbeni and Jomsom, and there is a reason it starts on schedule every day.

Sources: WorldAtlas, “10 Deepest Canyons in the World”; Wikipedia, “Kali Gandaki Gorge”; The Conversation (shaligrams).

Cover photo: Abdul Kayum via Pexels (Pexels License). Section photos: xing Wang via Pexels (Pexels licence); David Bartus via Pexels (Pexels licence); photowithom via Pexels (Pexels licence).