The peninsula tapers to a windswept point known as Cape Africa, capped by a working lighthouse and the ruins of the Borj el Kebir fortress. The walk out along the ramparts takes about twenty minutes from the medina and is worth it for the view alone — open sea on three sides, with the sailors' cemetery sloping down to the waterline.
The fortress was built by Fatimids, rebuilt by Hafsids, and finally enlarged by the Ottomans. From the top of the walls you can pick out the rectangular outline of the ancient harbour cut directly into the rock — the only Punic-style port still visible in Tunisia.