The Fortaleza de Santa Bárbara, also called El Castillo, sits on a low headland just east of the town centre with views over the entire sweep of Trujillo Bay. The current stone walls date from the 17th and 18th centuries — the original 1520s structure was repeatedly destroyed and rebuilt as pirates, the British, and finally American filibusters took turns sacking the port.
Inside the walls are the remains of barracks, a powder magazine, and the cannon emplacements that once defended the bay. The view from the ramparts, taking in the long beach, the bay, and the Capiro–Calentura hills, is the best in town. A small admission fee; explanatory signs in Spanish. Walking up from the central plaza takes ten minutes.