The ruins of the Ksar el Klali fort occupy a cliff east of the modern town, commanding wide views over the Adrar plateau and the wadi below. Built during the town's caravan-era heyday — when Ouadane was a major waypoint on the gold and salt routes between Morocco and sub-Saharan Africa — the ksar is a labyrinth of collapsed coral-stone walls, narrow lanes, and roofless houses gradually being reclaimed by the sand.
Walking through the ruins takes about an hour. The stonework is remarkable given the remoteness: the builders used the same reddish local stone as in the region's other ancient ksour, fitted without mortar into thick defensive walls. A local guide can point out which structures were merchant houses, which were storage rooms for caravan goods, and where the wells once stood.