With many such structures dotted around Northern Ireland, they are certainly well worth a visit, with their stunning windows onto the past.
Here are some suggestions for a memorable day out.
1. Carrickfergus Castle
Its keep may date back to 1177, but despite numerous sieges by the English, Irish, Scottish, and French, this imposing structure on the shore of Belfast Lough remains one of the best preserved medieval structures in the British Isles. Being in military use until 1928, explore the sprawling grounds along with genuine 17th and 19th-century cannon, along with the fully restored Great Hall with its new roof. For more information, go to discovernorthernireland.com/things-to-do/carrickfergus-castle-p674971 Photo: DiscoverNI
2. Belfast Castle
Overlooking Northern Ireland’s capital from the slopes of Cave Hill, a castle has existed on this site since at least the late 12th century, while the current structure was erected in 1870 by the third Marquis of Donegall of the Chichester family. Re-opening following a £2 million refurbishment programme in 1988, the Castle remains a popular wedding venue, with various events throughout the years. After dining at the Cellar Restaurant and Cellar Tavern, walk off lunch on the Castle estate, offering expansive views of Belfast, an abundance of such wildlife as sparrowhawks and long-eared owls, and the town hall clock - Belfast’s rarest plant. For more information, go to belfastcastle.co.uk/ Photo: DiscoverNI
3. Dunluce Castle
Overlooking the north coast outside Portrush, this collection of picture-perfect ruins dates back to the 16th and 17th centuries, when it was built by the McQuillan family. In the early 17th century, the castle even saw the growth of a small town outside its walls as it served as the seat of the Earls of Antrim. Hear tales of the ghostly banshees that roam the estate, as well as how the castle kitchen collapsed into the sea during a storm in 1639. The inspiration for C.S. Lewis to create Cair Paravel in his Narnia books, prepare to experience medieval life on the edge - literally. For more information, go to communities-ni.gov.uk/heritage-sites/dunluce-castle Photo: DiscoverNI
4. Castle Ward
More of a country house than a castle, this fabulous property near Strangford is truly one-of-a-kind - a marital dispute resulted in one side of the mansion being constructed in Gothic style, while the other half was modelled along Palladian lines. Feel free to explore the 32 kilometres of trails throughout the estate grounds, whether on horseback, on bike or on foot, and drink in the wonder of the artificial lake Temple Water, tranquil rest spots, and the Secret Shore Nature Trail. After exploring the Georgian farmland, be sure to visit the historic stable yard with its tea room, shop and secondhand bookshop. For more information, go to nationaltrust.org.uk/visit/northern-ireland/castle-ward Photo: DiscoverNI