Rub' al Khali

The Rub' al Khali, meaning Empty Quarter in Arabic, is a vast sand desert covering the southern third of the Arabian Peninsula across Saudi Arabia, Oman, the United Arab Emirates and Yemen, and forms part of the larger Arabian Desert system. At about 650,000 square kilometers, it ranks among the world's largest sand deserts, measuring roughly 1,000 kilometers long and 500 kilometers wide. Its dunes rise as high as 250 meters and take on a reddish-orange color from feldspar minerals in the sand, interspersed with gravel and gypsum plains, and its elevation ranges from about 800 meters in the southwest down to near sea level in the northeast.