The Spanish Fort (Fort d'Espagne, al-burj al-isbanyul) is the small angular fort perched on a hillside behind the medina, looking out over the old port, the canal, and the Mediterranean beyond. The walls are short and thick, with shaped gun ports on three sides — a late-Renaissance "trace italienne" design adapted for cannon fire across the harbour.
It is the best viewpoint in Bizerte. The walk up from the old port takes about fifteen minutes through the upper medina; the climb is steep but the lanes are interesting on the way. From the upper terrace you can see the entire old harbour, the city laid out below, the modern port, and on a clear day the Cap Blanc headland to the north.
The fort itself is unrestored and largely empty, which is part of the appeal. There is usually nobody else up there. Free; open during daylight hours.