For 15 points, identify this desert located in northern Yemen and Oman as well as southeastern Saudi Arabia, sometimes called The Empty Quarter.
Bertram Thomas was the first European to cross this region, and Iram of the Pillars is a legendary city of the people of 'Ad at the site of a collapsed limestone cavern in it. St. John Philby searched in this area but only ended up finding freshwater clam shells and hippo teeth in the Mudafan sector, and there are several meteor craters at Al-Hadidah. Bounded on the east by the Hajar Mountains and the west by the Asir Mountains, many caravan routes crossed this from the Frankincense-producing areas near Salalah. The Shaybah field is located on the northern edge of this area, while further to the west in this region is the Ghawwar oil field, which is the world's largest. For 15 points, identify this desert located in northern Yemen and Oman as well as southeastern Saudi Arabia, sometimes called The Empty Quarter.
Bertram Thomas was the first European to cross this region, and Iram of the Pillars is a legendary city of the people of 'Ad at the site of a collapsed limestone cavern in it.
Rub al Khali [accept Empty Quarter before read]