Dún na Séad, "fort of the jewels", is the tower house above Baltimore harbour that gives the village its Irish name. It was the seat of the O'Driscolls, and there has been a fortification here since at least the early 13th century, built over a still older ring fort. The castle has been destroyed and rebuilt several times; the present building dates from the 17th century.
It fell derelict in the 20th century, then was bought and restored by the McCarthy family in the late 1990s and partly opened to the public in 2005. The Great Hall has an exhibition on local piracy, but you mainly come for the view from the battlements. It's open daily from April to October; adult tickets were €6 in 2025.