English: Some of the "whirling dervishes" at the Al Nil (or Al Neel) mosque in the Omdurman area, just outside the Sudanese capital of Khartoum. The dervishes practice the Sufi style of Islam. Sufism is sometimes known as “Islamic mysticism.” The ceremony ceremony is held each Friday just before sunset, except during Ramadan, and features music, chanting, and the burning of frankincense. Some participant whirl around while most walk slowly in a large circle.