Saudi Arabia and parts of Oman, the United Arab Emirates, and Yemen. St. John Philby (who preferred the name "Wabar" for the lost city) was an English adviser to Emir Aziz bin Saud in Riyadh. He first heard the story of Ubar from his Bedouin guide, who told him about a place of ruined castles where King Ad had stabled his horses and housed his women before being punished for his sinful ways by being destroyed by fire from heaven. Anxious to seal his reputation as a great explorer, Philby went in search of the lost city of Wabar but, instead of finding ruins, discovered what he described as an extinct volcano half-buried in the sands or, possibly, the remnants of a meteorite impact. Modern research has confirmed an ancient impact event as the cause of the depression in the sands. Geologist H. Stewart Edgell observed that for the "last six thousand years the Empty Quarter has been continuously a sand-dune desert, presenting a hostile environment where no city could have been built." Shisr Nicholas Clapp claimed that the discovery of the remains of towers at the Shisr excavation site supported the theory that this was the site of Ubar, the city of 'Ad with "lofty pillars" described in the Qur'an. Thomas dismissed the ruins at the well of Ash Shisur as a "rude" fort which he took to be only a few hundred years old. Omanum Emporium Ranulph Fiennes, explorer and adventurer, was a member of Clapp's expedition and speculated that Ubar was identified on ancient maps as "Omanum Emporium". This was a place marked on a map of Arabia compiled by Claudius Ptolemy in about 150 AD. Others When the explorer Freya Stark consulted the works of Arab geographers, she found a wide range of opinions as to the location of Wabar: "Yaqut says: "In Yemen is the qaria of Wabar." El-Laith, quoted by Yaqut, puts it between the sands of Yabrin and Yemen. Ibn Ishaq… places it between "Sabub (unknown to Yaqut and Hamdani) and the Hadhramaut". Hamdani, a very reliable man, places it between Najran, Hadhramaut, Shihr and Mahra. Yaqut, presumably citing Hamdani, puts it between the boundaries of Shihr and Sanaʽa, and then, on the authority of Abu Mundhir between the sands of B.Sa'd (near Yabrin) and Shihr and Mahra. Abu Mundhir puts it between Hadhramaut and Najran." "With such evidence," Stark concluded, "it seems