The lively city of Sousse was built by the Phoenicians in the ninth century. A town that was Punic, Roman and then Muslim, Sousse has retained a great deal of its original character and is Tunisia's third largest city. Surrounded by authentic crenellated ramparts, it is dominated on one side by the Great Mosque and the elegant Ribat, Sousse's other great Islamic monument. If you climb the tower, you are rewarded with a magnificent view across the medina, the port and the Great Mosque. In the southwestern corner of the medina is the Kasbah, constructed around the ninth century Khalef el Fela watchtower, which houses the town museum and an impressive collection of mosaics.