The Castle of Lorca, known as the Fortress of the Sun, is one of Spain's largest castles, spanning 640 meters in length and rising from a hilltop commanding the southeastern Iberian frontier. Constructed between the 9th and 15th centuries and designated a Site of Cultural Interest, this medieval stronghold played a crucial strategic role during the Christian Reconquista, defending the border between the kingdoms of Murcia and Granada. The fortress features a polygonal layout divided into three sections, including the 15th-century Alfonsí Tower with Gothic vaulted ceilings. Uniquely, it preserves an exceptional medieval Jewish Quarter containing a rare synagogue never converted to Christian use, now presented as a themed heritage interpretation site.