The Wakhan Corridor exists because two empires did not want to share a border. In 1895 Britain and Russia drew a finger of mountain 350 kilometres long onto the map and handed it to an Afghan emir who had never asked for it, so that their territories would not touch. What they drew is walled by the Pamir to the north and the Hindu Kush to the south, with a river along its floor and some eighteen thousand people on it. An unpaved track follows the water up, squeezing through a narrowing gorge with the river beside you running grey with glacial silt. Then the walls let go. The valley opens into flat green pasture where the villagers' horses graze loose, and the snow-streaked wall of the Hindu Kush stands straight up behind them.
The villages down the valley are Wakhi, and they take you into the house itself. It is one square room under five wooden pillars, each standing for one of the five holy figures, with a stepped skylight over the cushions you sleep on. Past the last village there is no road at all. A trek of several days with pack horses takes you over 4,000-metre passes onto the open Pamir. The Kyrgyz camps show up as low domes on grass that runs to the horizon, yaks grazing loose around them. The households move with the pasture, so the same camp stands somewhere else the following summer. Permits and a guide are arranged long before anyone sets out, and the passes are open only in the short summer. The slopes hold Marco Polo sheep, whose horns can span 140 centimetres and which are named for the traveller who wrote them down here in the thirteenth century. Snow leopards hunt them. The Kyrgyz on the plateau are there by choice. In 1978 their khan led more than 1,300 of them out of the Little Pamir, and after four hard years in Pakistan, Turkey took them in and built them a village near Lake Van called Ulupamir. A few dozen families refused to go, and their descendants are still grazing the same grass.