San Felices de los Gallegos' Castle served as a crucial frontier stronghold between Portugal and Castile in Salamanca province, built in the 13th century by Portuguese King Dinis and completed in the 15th century. The impressive palace-fortress features a distinctive keep with three floors, including the Historic Hall of the town and exhibits on frontier fortifications. The complex comprises multiple defensive enclosures including a 13th-century stone wall with adjoining square towers encircling a spacious bailey, a 15th-century keep, and 17th-century bastioned walls, creating a layered defense system. The irregular design adapts to the natural terrain, with traces of ancient moats and walls still visible throughout the old quarter, which holds Cultural Interest designation.