The Djembe can be found all over Africa (and indeed all over the world these days) but dominates the music of Ghana. It is a wineglass-shaped drum that has two fundamental tones. The higher pitched tone comes from rim strikes which resonate in the top bowl of the Djembe. The low tone is produced by center strikes which cause a column of air to move through the narrow base of the drum causing a deep organ-like bass note.
Often metal panels covered with jingles are stuck into the strings to give sharp treble accents to the strikes.
The djembe rhythms are usually fast rolls alternating between the rim and center which accompany athletic dances before the onlookers. More on djembe Drumming recording from Senegal: https://audioboom.com/posts/188437-djembe-drumming-in-senegal
Videos from Seattle's Festival of West Africa: https://www.youtube.com/watch?v=LGZfjd4JINY&index=1&list=PLsKZCk3WZZpdXdK41LB0RtRDdlxTdVODl