Birr Castle

Birr Castle in County Offaly, Ireland, is the ancestral seat of the Earls of Rosse, its Victorian castellated silhouette having shaped the town of Birr for generations. The estate gained remarkable scientific significance in 1845, when William Parsons, 3rd Earl of Rosse, completed the Leviathan of Parsonstown here — a reflecting telescope with a 72-inch mirror that remained the world's largest until 1917 and first revealed the spiral structure of what we now call galaxies. A working reconstruction of the Leviathan stands in the castle grounds today. The surrounding demesne encompasses formal gardens, rare tree specimens, and walks along the Little Brosna river, making it one of Ireland's most distinguished historic garden landscapes.