The Fortezza Vecchia (Old Fortress) stands at the edge of Livorno's harbour, built by the Medici in the early 16th century around an older medieval tower. The design is attributed to Antonio da Sangallo the Elder and Giuliano da Sangallo, and the result is a dramatic piece of military architecture: circular bastions, a deep moat, and massive stone walls that still show the cannon ports designed to defend the port against naval attack.
The fortress is regularly open for visits, particularly in summer when concerts and events are staged inside the walls. The view from the ramparts over the harbour, the port cranes, and the Tyrrhenian Sea is excellent. The setting next to the Medicean Port makes it easy to combine with a walk along the waterfront.