Castelo de Lindoso

Built during the reign of Afonso III, this 13th-century castle 5km from the Spanish border long served as a key Portuguese military outpost. These days it's one of Peneda-Gerês' most photogenic attractions, with a vast collection of espigueiros spreading beneath its crenellated walls, all set against a dramatic mountain backdrop. You're free to walk around the castle perimeter; alternatively, a small admission fee grants access to a historical museum inside the main tower, with exhibits in Portuguese.