Dunluce Castle is the most dramatically positioned ruin in Ireland: a medieval fortress on a basalt stack above the Atlantic, connected to the mainland by a narrow bridge, with sections of its walls already tumbled into the sea below. The ruined towers and curtain walls photograph well in almost any light and from almost any angle.
The MacDonnells of Antrim, a Scottish clan who came over from the Hebrides, held the castle from the mid-15th century. At its peak it was a substantial fortified complex — the mainland side of the approach had its own fortifications, and a cave below the castle was used as a harbour for small boats. The Girona, a ship from the Spanish Armada that sank nearby in 1588 with the loss of nearly 1,300 lives, was salvaged in the 1960s; some of its recovered treasure is now in the Ulster Museum in Belfast.
The castle is managed by the state heritage service and has a modest but useful exhibition on the site history. Allow 45 minutes. It is 9 km from Portrush along the coast road toward Bushmills.