Conolly's Folly (also known as "The Obelisk") is an obelisk structure. It is built to the rear of Castletown House which contains two follies, both commissioned by the widow of Speaker William Conolly to provide employment for the poor of Celbridge at a time when famine was rife. As such these monuments serve no real purpose, instead they were dedicated to battles in the 16th century. The Obelisk was built in 1739 after a particularly severe winter. Designed by Richard Castle, it is 42 metres high and is composed of several arches, adorned by stone pineapples and eagles.