Lost Treasures of Arabia: The Nabataean Kingdom In ‘the Lost Treasures of Arabia: The Nabataean Kingdom’ episode, we will look at Hegra, a UNESCO World Heritage Site, that was the principal southern city of the Nabataean kingdom, famed for its spectacular monumental tombs. Although Hegra is lesser known to the general public, it’s an important place to understand this highly advanced Nabataean society.