vast desert in the southern Arabian Peninsula, covering about 250,000 square miles (650,000 square km) in a structural basin lying mainly in southeastern Saudi Arabia, with lesser portions in Yemen, Oman, and the United Arab Emirates. It is the largest area of continuous sand in the world. It occupies more than one-quarter of Saudi Arabia. The topography is varied. In the west the elevation is as high as 2,000 feet (610 m) and the sand is fine and soft, while in the east the elevation drops to 600 feet (183 m) with sand dunes, salt flats, and sand sheets. One of the driest regions in the world, it is virtually uninhabited and largely unexplored. However, in 1948 Al-Ghawār, the world's largest oilfield, was discovered there. For convenience several townlike names were given to different locations along the field.