Built as an ‘eye-catcher’ by the 3rd Marquis of Lansdowne when it was at the edge of the Bowood estate. It commemorates one of his ancestors, Sir William Petty (1627-1684) physician and surveyor.
Standing at 120 foot (38m), the stone obelisk was designed by Sir Charles Barry, architect of the Houses of Parliament and Highclere Castle.
The monument was acquired by the National Trust in 1988.