The Mahdi's Tomb - Omdurman, Sudan. Tomb of Muhammad Ahmad, self- declared Mahdi in 1881. In his reform of Islam he replaced the pilgrimage to Mecca with the obligation to serve in the holy war against unbelievers. The tomb was destroyed by the British after their conquest of Sudan as can be seen in this photograph. The tomb was rebuilt in 1947 as a copy of the original.