Castell de Fels, situated on a 59-meter hill in Castelldefels near Barcelona, is a frontier fortress originally built in the 10th century on Iberian and Roman ruins dating to the 3rd century BCE. Constructed to defend Carolingian Empire territories against the Caliphate of Córdoba and Arab pirate attacks, the castle featured a former parish church of Saint Mary within its outer walls. By the late 19th century, the fortress had largely fallen into ruin until banker Manuel Girona undertook comprehensive restoration in 1897. Medieval defense towers, including Can Ballester and Barona tower, date from the 16th century. During the Spanish Civil War, it served as a military training center and later as a prison. Today, it overlooks the southern Llobregat Delta with views extending to the Garraf Massif and Barcelona skyline.
