The Sahara Desert covers much of northern Africa, spanning across several countries including Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Sudan, and Tunisia. It is the largest hot desert in the world, with an area of approximately 9.2 million square kilometers (3.6 million square miles). The Sahara is characterized by its harsh climate, limited precipitation, and vast landscapes of sand dunes, rocky plateaus, and gravel plains. Despite its extreme conditions, it hosts a variety of ecosystems and cultures, making it a unique area of study in terms of geography and anthropology.