In the south of the Kingdom is the famous Rub al-Khali (the Empty Quarter), a massive, trackless expanse of shifting sand dunes - one of the largest sand deserts in the world - which covers an area of more than 250,000 square miles (650,000 square kilometers) and extends to 1,200 by 500 kilometers.
The Rub al-Khali is one of the driest places on earth, receiving almost no rain at all. Nevertheless, many parts of this dry desert support some hardy plants (in particular, the scarlet-fruited abal and the hadth saltbush).
