Every Friday dervishes gather an hour before sunset around some of the big mosques in Khartoum and Omdurman. A circle is formed and the ritual begins. According to ancient belief, Sufism is about the purification of the soul in pursuit of inner peace. The whirling dance came from the Mevlevi Order in Turkey, and is just one of the physical methods used to try to reach religious ecstasy. At the close of the ceremony, just before sunset, one of the dervishes walks round the gathered audience with frankincense - which is considered to be a type of blessing to the faithful.