Located in the northwest of Saudi Arabia, AIUla (al-'Ulā) is a spectacular natural and archaeological region. This book tells its thousand-year-old history, from the first human settlements seven thousand years ago to modern times. We also discover the vitality of the archaeological research carried out for nearly thirty years, in particular by the Franco-Saudi teams. The geological formation of the valley and its oases, the worship practices of the ancient pre-Islamic kingdoms, the majesty of the Nabataean rock tombs, the birth of Arabic writing, the life of pilgrims at al-'Ulā, the time of a stopover on the road from Damascus to Medina, the construction of the Hijaz railway attest that this place, too long ignored, is at the crossroads of civilizations. In al-'Ula, the Hegra of the Nabataeans and the Romans, the first Saudi archaeological site inscribed on the UNESCO World Heritage List in 2008, is opening up to the world. Comparable to Petra, in Jordan, by its size and its importance, Hegra conceals secrets, revealed during an exhibition.