Saudi Sand Dunes 1

In the southern Arabian Peninsula, the world's largest expanse of sand stretches for 250,000 square miles. The Ar Rub' al-Khali, or Empty Quarter, is the king of all Middle Eastern deserts. The rare unbroken sweep of pure sand was formed over eons as water and wind eroded volcanic highlands and dry seabed’s down to pebbles and grains, which were blown into huge dunes, some nearly 1,000 feet high. In this image, the yellow areas are sand dunes, and the blue areas are dry inter-dune lake beds. This image was acquired by the Landsat ETM satellite in September 2001, and is centered at 22.1794, 54.2458.