sand dune. The fort had been built from the same white rock as the overhanging cliff, giving the impression of a single structure. One of the geologists noted: "There are no houses, tents or people here: only the tumble-down ruin of this pre-Islamic fort." The geologists, without the benefit of modern satellite analysis or archaeological equipment, were unimpressed by the ruin. Shisur, like Ma Shedid a few days before, was a 'difficult water' and their escorts spent the best part of their 3-day stay trying to extract water for their camels from the well. In 1953, oil man and philanthropist Wendell Phillips set out to discover Thomas' track but was unable to follow it because of the heavy sands which made further travel by motor transport impossible. Some 35 years later, Clapp and his team reported uncovering what they described as a large octagonal fortress dating back some 2,000 years beneath the crumbling fort, and described a vast limestone table that lay beneath the main gate which had collapsed into a massive sinkhole around the well. This, some concluded, was the fabled city of Ubar, which was also known as Iram, or at least a city in the region of Ubar, once an important trading post on the incense route from Dhofar to the Mediterranean region. Some pointed to religious texts to support the theory that the city was destroyed as a punishment by God. Iram, for example, was described in the Qur'an as follows: "Have you not considered how your Lord dealt with 'Aad - [with] Iram - who had lofty pillars, The like of which were not produced in (all) the land?" (Surat al-Fajr: 6–8) Theories about the location Dhofar Bertram Thomas' guide pointed to wide tracks between the dunes and said: "Look, Sahib, there is the way to Ubar. It was great in treasure, with date gardens and a fort of red silver. It now lies beneath the sands of the Ramlat Shu’ait." Thomas also wrote, "on my previous journeys I had heard from other Arabs of the name of this Atlantis of the Sands, but none could tell me of even an approximate location." Rub' al-Khali Most tales of the lost city locate it somewhere in the Rub' al Khali desert, also known as the Empty Quarter, a vast area of sand dunes covering most of the southern third of the Arabian Peninsula, including most of