Built atop a rock ledge in 1180 by John de Courcy, provincial Ulster's first Anglo-Norman invader, Carrickfergus Castle is still in good shape and since 2014 has sparked renewed visitor appeal with the opening of its dungeons. Apart from being captured briefly by the French in 1760, the castle—one of Ireland's largest —stood as a bastion of British rule until 1928, at which time it still functioned as an English garrison. Walk through the 13th-century gatehouse into the Outer Ward and continue into the Inner Ward, the heart of the fortress, where the five-story keep stands, a massive, sturdy building with walls almost 8 feet thick. And make sure you venture down the steps into the dark stone dungeons, opened as part of a renovation project which also saw the roof of the Great Tower replaced and the opening of an ammunitions room. If you're here at the end of July, you can enjoy the annual Lughnasa festival, a lively medieval-costume entertainment.
Off A2, Marine Hwy., Carrickfergus, Co. Antrim, BT38 7BG, Northern Ireland