Mada’en Saleh, also known as Al Hijr, is a series sandstone outcrop of various sizes and heights surrounded by a ring sand mountains. It is a pre-Islamic archaeological site located in the Al-Ula sector, within the Al Madinah Region of Saudi Arabia. http://www.sauditourism.sa/en/ExploreKSA/AttractionSites/AlolaAndMadaenSaleh/Pages/default.aspx