The Sahara (Arabic: الصَحراء الكُبرى, aṣ-ṣaḥrā´ al-koubra, "The Great Desert") is the worl's largest hot desert and the world's second largest desert after Antarctica . At over 9,000,000 square kilometres (3,500,000 sq mi), it covers most parts of Northern Africa; an area stretching from the Red Sea, including parts of the Mediterranean coasts, to the outskirts of the Atlantic Ocean. To the south, it is delimited by the Sahel, a belt of semi-arid tropical savanna separating the Sahara from Sub-Saharan Africa.