The oldest mosque in Africa, prayers are still held in this large mosque dating back to 641 CE. Muslim leader Amr Ibn el-Aas is said to have ordered its construction upon receiving a sign from God in the form of a dove nesting in his tent. When the doves brood was raised, the mosque was built on the site. It has been altered throughout the centuries and incorporates many different styles. No two of its 150 columns are identical.