With over 3,000 castles dotted across the island of Ireland, it would be impossible to visit them all. Here we take a closer look at six of the castles that are open to the public, from cliff-side promontory to inland oasis. Dunluce Castle Dunluce Castle At the tip of the Antrim coast sits the sprawling Dunluce Castle, looming over the sea atop a dark basalt outcrop. Once home to the feuding McQuillan and MacDonnell clans, this is the quintessential medieval Irish castle. From rebellion to fire, mermaids to banshees, Dunluce has seen its fair share of drama. No wonder, then, that this much-storied pile is said to have inspired C.S. Lewis to create Narnia’s hallowed Cair Paravel. With the white chalk cliffs of Portrush sweeping away to the west, you could be forgiven for thinking you’d stepped back in time. But don’t get too close to the edge – local legend says the castle kitchen once collapsed into the sea, dragging seven cooks with it. Glenarm Castle Glenarm Castle While the present castle has stood since 1636, there has been a castle at Glenarm since the 13th century. Once stretching all the way up the northern coast of Antrim, today’s Glenarm estate is now much smaller, housing an organic farm instead of a deer park and a charming Tea Room where the 19th century Mushroom House once sat. Though still a family home, guided tours of the Castle are available at selected times. The grounds are a hive of activity, hosting the Highland Games for the past number of years, as well as the 10-mile Wilderbeast trail run, and an annual Tulip Festival. And, with the seaside a short stroll away, what more could you want? Tullynally Castle Tullynally Castle Occupied by the same family since the 17th century, Tullynally Castle is linked to one of Ireland’s best-loved legends, The Children of Lir. Indeed, visitors reported that a ‘fairy land’ had been constructed on the site in the 1830s, when Lady Georgiana remodeled the grounds. Although everything from a llama paddock to a Tibetan Garden has since been added, the castle itself has remained largely unchanged. Centuries later, the flawless acoustics of Tullynally’s magnificent Great Hall sees it host regular music events, while visitors to the expansive gardens can often catch a plant fair or owner-led spring walk. From summer fêtes to Halloween Terror Trails, Tullynally truly is a castle for all seasons. Birr Castle Birr Castle The Third Earl of Rosse was an innovative gent. His Leviathan telescope, still in working order at Birr Castle, was once the largest in existence, and his wife Mary created one of the world’s first darkrooms in the estate stables. It’s not difficult to see why – Birr Castle Gardens are some of the most stunning in Ireland. Endless exotic flowers enliven the grounds in a rainbow of colour, while waterfalls and lakes are home to otters, herons and kingfishers. Within the castle, visitors are guided by descendants of the Earl and his wife, whose portraits still adorn the great Victorian dining room. The view from the spectacular, octagonal Gothic Saloon drinks in the River Camcor, from where the couple’s son once harnessed the current to provide Birr with electricity. Blackrock Castle Blackrock Castle Cork’s coat of arms heralds the city as a “safe harbour for ships”, but this wasn’t always the case. The formidable limestone outcrop of Blackrock Castle was built in the 16th century to protect one of the deepest natural harbours in the world from pirate and naval attacks – and to protect the nobility from the rowdier factions within the Rebel County. Twice destroyed by fire, the castle was faithfully restored by the people of Cork. Today, it is home to the invaluable astronomical research centre of the nearby Cork Institute of Technology. Its award-winning interactive astronomy exhibition, Cosmos at the Castle, is the first of its kind in Ireland. Ballynahinch Castle Ballynahinch Castle Tucked away among 180 hectares of rugged Connemara landscape, Ballynahinch Castle is a safe bet for those seeking a relaxed setting. In its old age, the estate has mellowed, but half a millennium ago, it was home to some of the most infamous figures of Irish legend. Pirate queen and chieftain, Grace O’Malley, and the ‘Ferocious O’Flaherty Clan’ all graced its halls. The grounds of Ballynahinch can be easily enjoyed on horseback or on foot, while seasonal woodcock shoots and a trip to the deserted Inishlacken island are particular visitor favourites. Those who prefer to appreciate the historic surrounds from a more comfy location can cuddle up in a fireside armchair. Explore more Ireland's unmissable castles: Part 2Explore six more of Ireland’s unmissable castles. Living History Play heir to the estate in these inhabited castles. Ireland’s ‘Big Houses’See Ireland bloom in these three gems.