In Salah's interest is mainly in what it is — an oasis in one of the most extreme environments on earth — rather than in any specific monument. The old ksar, the surrounding date palmeries, and the ingenious foggara irrigation system that has kept the town alive for a thousand years are the things to see. The famous "moving dune" — a sand mountain that the town's residents have been trying to outrun for generations — sits on the northern edge.