Ad-Dahna Desert passages which can be several kilometers long. Local Bedouin have always known these caves and some were used as water supplies. They were first systematically studied in the 1981, and later explored and reported by the Saudi Geological Survey. Ad-Dahna Desert The ad-Dahna Desert is the central division of the Arabian Desert. It is a corridor of sandy terrain forming a bow-like shape that connects an-Nafud desert in the north to Rub' al-Khali desert in the south. Its length is more than 1,000 km siding Twaik Mountains from the east and does not exceed 80 km in width. It is
Gobi Desert Water is scarce, with no streams, no lakes, no wells, and precipitation falls seldom. The prevailing winds blow from the west and northwest, and the pall of dust overhangs the country as in the Takla Makan and the desert of Lop. Characteristic of the flora are wild garlic, "Kalidium gracile", wormwood, saxaul, "Nitraria schoberi", "Caragana", Ephedra, saltwort and the grass "Lasiagrostis splendens". The taana wild onion "Allium polyrrhizum" is the main browse eaten by many herd animals, and Mongolians claim that this is essential to produce the correct, slightly hazelnut-like flavour of camel airag (fermented milk). This great desert country