The Castelo de San Carlos sits at the edge of the Atlantic in Fisterra, a Costa da Morte municipality in Galicia, constructed during the mid-18th century as a coastal fortress. Built by engineers Demaur and Exaccha under King Charles III's orders, the castle was designed to protect the Corcubión estuary against the frequent English and French privateering raids that threatened Galician waters during the 17th and 18th centuries. Its irregular architectural form adapts strategically to the rugged rocky coastline, making optimal use of its dramatic seaside location. Today, the fortress houses a fishing museum and serves as a principal tourist attraction, welcoming visitors who explore its exhibits and enjoy views of this historically significant defensive outpost.