Gosaikunda is a glacial lake at 4,380 metres in the Langtang mountains of Nepal, north of Kathmandu, and for one night a year it is among the most crowded places in the Himalaya. On the August full moon tens of thousands of pilgrims fill the shore through the night and wade into the near-freezing water at dawn, believing it washes away sin. The lake is Shiva's. In the story he swallowed a poison that would have destroyed creation, and to cool his burning throat he struck these mountains with his trident; the three springs that opened are said to feed the lake still. The dark rock you can see breaking the surface near the middle is revered as his shrine, and many hold that a form of the god lies resting under the water. The festival is Janai Purnima, when Hindu men bathe and replace the janai, the cotton thread worn across the chest, and others knot a protective cord round the wrist. Shamans from the hill villages, the jhankri, drum and dance in trance beside you until first light.
The pilgrims walk up from Dhunche, and so do you. The trail climbs for two or three days through rhododendron forest into open pasture, past mani walls and lines of prayer flags. The air thins fast enough that most people sleep a night halfway up before the final rise. The basin that opens at the top is bare granite, with the water dark at the bottom of it. Above the lake, the flag-hung Lauribina ridge sets the snow-veined Langtang peaks in a line across the horizon, and the sacred basin lies far below you. Gosaikunda is one of more than a hundred lakes in this high cirque, each with its own standing in the pilgrimage. The great night falls in the middle of the monsoon, so the mountains around it are usually in cloud; the clear skies and the sharp peaks belong to October, when the shore is quiet again. Then the cold comes down, the surface freezes over, and the shrine spends the winter under ice.