This area forms a passageway from Petra towards Wadi Araba and Bir Madkhur, which was a major caravan station along the ancient trade route that linked Petra to the Mediterranean port of Gaza. Several rock-cut cisterns, which were used to collect rainwater, and numerous dams, which controlled flood water, have been discovered in the area.   At the entrance to the gorge of Siq Umm al ‘Alda there are twin obelisk stelae carved on a rock surface; a Nabataean inscription associates the stelae with a shaft tomb.  Stelae, and the obelisk shape, are usually associated with burial and the souls of the deceased. The Nabataeans called them ‘nefesh’, which is similar to the Arabic word for ‘self’.   A Greek inscription in red ink, drawn near the stelae in about 416 AD, mentions a financial officer called Neros, who it seems was responsible for the area’s water systems and caravan roads.