Somalia is bordered by Ethiopia to the west, the Gulf of Aden to the north, the Somali Sea and Guardafui Channel to the east, and Kenya to the southwest. With a land area of 637,657 square kilometers, Somalia's terrain consists mainly of plateaus, plains and highlands. Its coastline is more than 3,333 kilometers in length, the longest of mainland Africa. It has been described as being roughly shaped "like a tilted number seven".