Birr Castle: The Leviathan of Parsonstown

The 3rd Earl of Rosse built the great telescope at Birr, and when it was finished in 1845 it was the largest on Earth, able to see further into space than any before it. His son, the 4th Earl, measured the heat of the moon. After 1908 the telescope fell into disrepair, the mirror went to the Science Museum in London and the iron frame was melted down around 1914 for the war; it was restored in the late 1990s, and you can stand under it again. The castle is still the Earl's home, but the demesne is open: a science museum with Mary, Countess of Rosse's darkroom, thought to be the oldest surviving in the world, a wrought-iron bridge of 1820, said to be the oldest in Ireland, and box hedges more than 300 years old in the walled gardens.