Wimpole's Folly is a folly ruins, meaning that it is fake ruins of a medieval castle. It was built on the grounds of Wimpole Hall, in the mid 1770's, at the order of Philip Yorke, 1st Earl of Hardwicke, the then owner of Wimpole Hall. The Earl of Hardwicke commissioned Mr. Sanderson Miller (the noted follies architect of the day) to design the folly in 1751, to then have it later built by 'Capability' Brown in 1769.
The ruins are substantially built and stretch for two hundred feet in length, and include a four story Gothic tower. They, and Wimpole Hall, are currently owned by the National Trust and open to the public.