Aerial view of old Ghardaia, the largest of the ancient hill towns in the M'Zab region, and a World Heritage Site. The villages of Ghardaia are all located on hills in the valley surrounded by a stony plain. The areas between the villages used to be all farmland, but a rapidly growing population has filled in most of the low-lying ground with residential buildings, which are susceptible to flooding from rare but severe thunderstorms.
