Sham Castle is a folly

Folly

In architecture, a folly is a building constructed primarily for decoration, but either suggesting by its appearance some other purpose, or merely so extravagant that it transcends the normal range of garden ornaments or other class of building to which it belongs...

 in Bathampton

Bathampton

Bathampton is a village and civil parish east of Bath, England on the south bank of the River Avon. The parish has a population of 1,504.The Kennet and Avon Canal passes through the village and a toll bridge links Bathampton to Batheaston on the north bank of the canal.-History:Bathampton Camp is...

 overlooking the city of Bath, Somerset

Somerset

The ceremonial and non-metropolitan county of Somerset in South West England borders Bristol and Gloucestershire to the north, Wiltshire to the east, Dorset to the south-east, and Devon to the south-west. It is partly bounded to the north and west by the Bristol Channel and the estuary of the...

, England. It is a Grade II* listed building. It is a screen wall with a central pointed arch flanked by two 3-storey circular turrets, which extend sideways to a 2-storey square tower at each end of the wall.

It was probably designed around 1755 by Sanderson Miller

Sanderson Miller

Sanderson Miller was a pioneer of Gothic revival architecture, and a landscape designer who often added follies or other Picturesque garden buildings and features to the grounds of an estate....

 and built in 1762 by Richard James, master mason for Ralph Allen

Ralph Allen

Ralph Allen was an entrepreneur and philanthropist, and was notable for his reforms to the British postal system. He was baptised at St Columb Major, Cornwall on 24 July 1693. As a teenager he worked at the Post Office. He moved in 1710 to Bath, where he became a post office clerk, and at the age...

, "to improve the prospect" from Allen's town house in Bath

Ralph Allen's Town House, Bath

Ralph Allen's Town House is a grade I listed townhouse in Bath, Somerset, England.Ralph Allen, commenced building it in or shortly afer 1727, although it is unlikely he ever lived there...

.

Sham Castle is now illuminated at night.