Kairouan is the 4th holiest city of Islam. The biggest attraction is the Great Mosque, dating all the way back to around 670 AD. Even if it's been modified and restored many times, the lower part of the minaret is thought to be dating back to the constructions of early 8th century, and if this is true, then it's the oldest standing minaret in the world. The mausoleum of Sidi Sahbi the barber got this name because here there used to be a barber who carried three hairs from the Prophet's chin around in his pocket. The prayer hall is not open to non-muslims but it's worth a visit to admire the columned courtyard and the charming and colourful tiles that decorate the walls.