While there are dunes in several places around Wadi Rum, the most striking are the red sands that bank up against Jebel Umm Ulaydiyya. If you are on a 4WD tour, drivers will stop near a pristine slope for you to plod your way to the crest of the dune. To reach the dunes on foot from the visitor centre takes three hours, partly through soft sand. They're particularly lovely at sunset.