Ross Castle, Killarney

Allegedly haunted by medieval ghosts, Ross Castle sits on the edge of Lough Leane, one of three interlinked lakes within the country's most popular national park. Built in the 15th century by the region's ruling O'Donoghue clan, the castle was among the last places in Ireland to succumb to the forces of Oliver Cromwell, who occupied the country in 1650. The castle's cunning defensive features include a spiral staircase designed with each step a different height, which helped trip up would-be attackers for over a century. You can see the unusual staircase and rooms filled with 17th century oak furniture by guided tour only, so be sure to book your tickets well in advance. A visit to Ross Castle represents just the start of the adventure when you use our Killarney trip builder to plot your vacation.