The westernmost of the three central routes was the Ghadames Road, which ran from the Niger River at Gao north to Ghat and Ghadames before terminating at Tripoli. Next was the easiest of the three routes: the Garamantean Road, named after the former rulers of the land it passed through and also called the Bilma Trail. The Garamantean Road passed south of the desert near Murzuk before turning north to pass between the Alhaggar and Tibesti Mountains before reaching the oasis at Kawar. From Kawar, caravans would pass over the great sand dunes of Bilma, where rock salt was mined in great quantities for trade, before reaching the savanna north of Lake Chad. This was the shortest of the routes, and the primary exchanges were slaves and ivory from the south for salt.