Bab Diwan — the Sea Gate — is the most ornate of the medina's historic entrances and the traditional main gate facing the harbour. It has been rebuilt and modified several times over the centuries but retains a handsome decorated arch that frames the entrance to the main commercial artery of the old city. The gate is flanked by sections of the original 9th-century walls, which here are well preserved and give a good sense of the fortification's scale.
The avenue leading from Bab Diwan into the medina interior is busy from early morning and is the best introduction to how the old city functions: shops, workshops, food stalls, and residents moving purposefully in all directions. The new town's main square is directly outside the gate, making it the natural starting point for a medina visit.