There are many examples of trance in religion. African animistic religions, such as that of the Yoruba, feature dances in celebration of the spirits. Under the influence of rhythm and song, a group dances, often for hours at a time. During this time, various members of the group may fall into trances, and some may act as if possessed by one of the spirits being worshiped. States of "spiritual ecstasy" are known in most forms of Christian worship. It is a main part of those aspects of religion known as "mysticism".