The Sahara Desert, which covers most of North Africa, is the largest desert in the world. It covers an area of approximately 3.5 million square miles. On the west, the Sahara is surrounded by the Atlantic Ocean and on the east by the Red Sea, and to the north are the Atlas Mountains and the Mediterranean Sea. Thy name “Sahara” cameos from the Arabic noun ‘sahra’, meaning desert, and it plural, ‘Sahara’. The sand dunes of the dessert are very big, so huge that they can go up to a height of 600 feet. Additionally, there are stone plateaus, salt flats, gravel plains and arid valleys. Sandstoms are very common in the desert. The highest part of the desert is at the summit of Mount Koussi, which is 11,204 feet (3,415 m) high. The lowest point of the Sahara is 436 feet (133m) below sea level in the Qattera Depression in Egypt. The plant life is thin with scattered concentrations of grasses and shrubs. There are many animals in the desert, including poisonous snakes and poisonous spiders, scorpions, monitor lizards, sand vipers, wild dogs, ostriches, cheetahs, among others.