To the north of the region lies the Sahel, a more arid Acacia savanna region that in turn borders the Sahara Desert further north, and to the east the Ethiopian Highlands (called "al-Ḥabašah" in Arabic). In the southwest lies the West Sudanian savanna, a wetter, tropical savanna region bordering the tropical forests of West Africa. In the center is Lake Chad, and the more fertile region around the lake, while to the south of there are the highlands of Cameroon. To the southeast is the East Sudanian savanna, another tropical savanna region, bordering the forest of Central Africa. This gives way further east to the Sudd, an area of tropical wetland fed by the water of the White Nile.