Traversing the Empty Quarter
Credit: Wilfred Thesiger / Wikipedia

The Rub' al-Khali ("Abode of Emptiness") remained one of the last prizes of terrestrial exploration well into the 20th century – and for good reason. It's the largest uninterrupted sand sea in the world, a dune-rippled wasteland covering a fifth of Saudi Arabia and bleeding into Yemen, Oman, and the United Arab Emirates. Temperatures can top 140°F; humidity can bottom out at almost zero. The Empty Quarter's only inhabitants are the nomadic Bedouin tribes that stick to its more hospitable fringes, but even then the term hospitable is relative. T.E. Lawrence characterized their existence as "a death in life." Lawrence also dismissed explorers' desires to traverse the Quarter, decreeing that "only an airship could cross it." Yet he was proved wrong within a few years. Bertram Thomas and Harry St. John Philby, British civil servants stationed in Arabia, both crossed the Empty Quarter in the early 1930s. Thomas did it first, leading a camel caravan across the shifting orange sands in 18 days. Philby, forced to make repeated starts due to heat exhaustion, did it harder. A convert to Islam who later went on to notoriety as a diplomat-cum-spy, Philby developed a profound attraction to the arid expanses, one that was shared, even more deeply, by his friend Wilfred Thesiger, the third great explorer of the Empty Quarter (see photos below). Thesiger made two epic crossings, but he was less concerned with geographical pioneering than with making contacts with Bedouin tribesmen and with his own philosophical affinities. "No man can live this life and emerge unchanged," he wrote. "For this cruel land can cast a spell which no temperate clime can match."