BIRR CASTLE DEMESNE | BIRR, COUNTY OFFALY
While you can’t tour Birr Castle as it’s privately owned, it’s the demesne that people come to visit. The science center in the renovated stables is filled with contributions made by the family of the Earls of Rosse in the fields of astronomy, botany, engineering and photography. Across the grounds, you’ll discover gardens, an early suspension bridge and the Great Telescope &emdash; the largest in the world until the mid-20th century. Recently, Birr Castle built Ireland’s largest treehouse which, in addition to the already large play area, will occupy children for hours.