The tiny Uighur settlement of Tongguzbasti, 170km (102 miles) north of Keriya beside the rapidly diminishing Keriya Dariya, must rank as one of the most remote places in Xinjiang. It is said to stand on the ruins of the lost city of Keladun, and artefacts dating from the Han Dynasty (206 BC-AD 222) have been found here. Today about 100 families of Keriya Uighur live here in almost complete isolation.