Wainhouse Tower is a folly in the parish of King Cross, on the south west side of Halifax, Calderdale, West Yorkshire, in England. At 275 feet (84 m), it is the tallest structure in Calderdale and the tallest folly in the world, and was erected in the four years between 1871 and 1875. The main shaft is octagonal in shape and it has a square base and 403 steps leading to the first of two viewing platforms. The tower is open to the public during bank holidays, and is a Grade II* listed building.