A region in west Africa that is bordered by the Sahara Desert to the North and tropical areas in the South. It is characterized by a savanna environment. Countries in the Sahel included Benin, Burkina Faso, Chad, The Gambia, Ghana, Guinea, Guinea-Bissau, The Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, and Togo.