The ruins of Dunluce Castle perch atop a dramatic basalt crag 5km east of Portrush, a one-hour walk away along the coastal path. A narrow bridge leads from the mainland courtyard across a dizzying gap to the main part of the fortress. Below, a path leads down from the gatehouse to the Mermaid's Cave beneath the castle crag. All coastal buses stop here.
In the 16th and 17th centuries the castle was the seat of the MacDonnell family (the earls of Antrim from 1620), who built a Renaissance-style manor house within the walls. Part of the castle, including the kitchen, collapsed into the sea in 1639, taking seven servants and that night's dinner with it.