This is a 21-string plucked harp-lute of West Africa, almost exclusively played by professional male musicians. Like almost all African harps and harp-lute hybrids, Mandinka koras are used for self-accompaniment. The kora is constructed of a large gourd, which is cut in half, some type of hide (usually cow hide), fishing line and wood. Leather rings are used to achieve proper tension on each string, and thus the instrument may be tuned. Most are built in Gambia, Senegal, Mali, and other areas of West Africa. The first known reference to it is in the 1799 book, Travels in the Interior Districts of Africa by an author with the unlikely name of Mungo Park.