SAUDI ARABIA - JANUARY 18:  Archaeological site in Madain Saleh, Saudi Arabia on January 18, 2010 - Madain Saleh in Saudi Arabia, a sister city to Jordan's Petra. UNESCO world heritage site. The archaeological site of Al-Hijr (Madain Salih) was formerly known as Hegra, it is the largest conserved site of the civilization of the Nabataeans south of Petra in Jordan. It features well-preserved monumental tombs with decorated facades dating from the 1st century BC to the 1st century AD. With its 111 monumental tombs, 94 of which are decorated, and water wells, the site is an outstanding example of the Nabataeans culture.  (Photo by Eric LAFFORGUE/Gamma-Rapho via Getty Images)