The Castle of San Julián is an 18th-century military fortress perched on a 293-meter mountain near Cartagena, Spain. Originally fortified in 1706 during the War of Spanish Succession with a cylindrical tower built by English Admiral John Leake, the fort was completed in 1888 after substantial reforms between 1861 and 1883. Designed to defend the mountain peak and dominate the port entrance, it served during the Spanish Civil War as a military prison for high-ranking commanders. Though freely accessible today, the structure remains largely intact but shows signs of age; modern telecommunications equipment now occupies the tower alongside the historic fortification.
