Shey Phoksundo National Park

Listen first. The wind moves over dry grass and loose scree. Somewhere below, water runs over stone. The air is thin and cold, even in sunshine, and every breath feels a little shorter than it should. The light up here is hard and clear, and the shadows have sharp edges. Welcome to Shey Phoksundo National Park, a high, wide wilderness in the far west of Nepal, where the Himalaya begins to give way to the dry Tibetan plateau.

You are in a very big place. This is the largest national park in Nepal. It was created in 1984, and its land stretches across the remote districts of Dolpa and Mugu. Much of it sits on the far side of the main Himalayan wall, in what geographers call the trans-Himalaya — the rain shadow beyond the great peaks. The monsoon clouds break against the southern mountains. Only a fraction of their rain reaches this side. That is why the slopes around you look brown and bare.

Look at the land closely, and it starts to make sense. The valleys are deep and narrow. The ridges are folded and layered, in bands of grey, rust, and ochre. Trees grow mainly in the lower, wetter valleys, with birch, pine, and juniper. Higher up, there is only grass, thorny shrubs, and rock. Above that, there is snow. In a single long day of walking, a traveller can pass through several of these worlds, one stacked on top of the next.

The park's best-known treasure is Phoksundo Lake. It lies more than 3,600 metres above sea level, and it is widely considered the deepest lake in Nepal. The colour is the first thing every visitor notices. On a bright day, the water turns a deep turquoise, almost unreal against the dun-coloured cliffs. The colour changes with the light — greener in the morning, darker blue under cloud, nearly black at the far end where the cliffs drop straight into the water.

Scientists believe the lake formed when a huge landslide blocked the valley long ago, and the river backed up behind it. Local people tell a different story. Legend has it that a village once stood where the water is now. According to one popular tale, a demoness fleeing a powerful religious master caused a flood that drowned the settlement. Locals say that on calm days, you can still sense the lost village beneath the surface. Whether you believe it or not, the story shows how closely the people here tie their landscape to faith.

That faith is the second surprise of this place. On the shore of the lake sits the village of Ringmo, with flat-roofed stone houses and stacked firewood on the rooftops. Not far away stands a monastery of the Bon tradition. Bon is an ancient religion of the Tibetan world. It shares much with Tibetan Buddhism, but it has its own lineage, its own saints, and its own rituals. One easy sign of the difference: Bon followers walk around shrines and prayer walls anticlockwise, the opposite direction to most Buddhists.

The people of this region are often called Dolpo-pa, the people of Dolpo. Their language, dress, and customs are close to those of Tibet. For centuries, families here have lived by herding yaks and goats, growing barley in short summers, and trading across the high passes. Salt from the north and grain from the south once moved on the backs of yak caravans. Some of that life continues today, though roads, schools, and mobile phones are slowly changing the valleys.

The wider region became known to many readers abroad through a book. In the 1970s, the American writer Peter Matthiessen walked deep into this country with the biologist George Schaller. They were studying blue sheep and hoping to glimpse a snow leopard. Matthiessen's account, called The Snow Leopard, describes the journey to Shey Gompa, a monastery near a peak known as Crystal Mountain. The book is part travel diary, part spiritual search. Many trekkers still carry a copy in their packs.

And the snow leopard is still here. The park is one of the important refuges for this shy cat in Nepal. You are very unlikely to see one — local herders may live a whole lifetime and see only a few. But you may see what it hunts. Blue sheep, also called bharal, graze on the steep slopes. Their grey-blue coats blend so well with the rock that a whole herd can be invisible until one animal moves. Look for them on the cliffs above the lake.

Other animals share these heights. Himalayan griffon vultures and lammergeiers ride the thermals above the ridges. The lammergeier, or bearded vulture, has a famous habit — it drops bones from a height onto rocks, then eats the broken marrow. Smaller birds flit between juniper bushes. Pikas, small round relatives of rabbits, whistle from the boulders. In early summer, local people also climb high to search for a valuable caterpillar fungus, which is sold for medicine and brings important income to the villages.

On the way up to the lake, many visitors pass a tall waterfall where the outflow of Phoksundo drops down a cliff face. It is one of the highest waterfalls in Nepal. Stand near the viewpoint and you can feel the cold spray in the air. Below the falls, the river cuts a narrow, roaring gorge. Above them, the trail climbs through birch and pine before the lake suddenly opens out in front of you. That first view is a moment many travellers remember for years.

The lake itself is treated as sacred. Local custom asks visitors not to swim or wash in it, and not to pollute it in any way. The park has also been recognised internationally as an important wetland. These rules matter more here than in many places. This is a fragile system. Soil forms slowly in the cold. Plants grow slowly. A trail scar or a pile of rubbish can last for decades. Walking gently is part of being a good guest.

Getting here is not easy, and that is part of the character of the park. There are no quick roads into its heart. Most visitors fly into a small mountain airstrip and then walk for days. A special permit is required for parts of the region, especially the restricted areas of Upper Dolpo. The effort filters the crowds. On many trails you may walk for hours and meet only a mule train, a monk, or a family moving their animals to new pasture.

Before you move on, take a moment. Look at the colour of the water, or the line of the ridge against the sky. Notice the prayer flags snapping in the wind, the smell of juniper smoke from a kitchen fire, the crunch of gravel under your boots. This landscape has shaped the people who live in it for many centuries. As you walk away, listen once more for the wind, the water, and the quiet in between.