Cromwell’s Castle is a substantial stone fortress which lies half a mile north of New Grimsby pier on the west side of the island of Tresco. It was built in 1651-52 to protect shipping in New Grimsby Sound from enemy Dutch fleets. Visible in this view is Hangman Island, which lies between Tresco and Bryher. Tresco is in two different halves, the north being bleak and rocky while the southern is the home of the famous Tresco Gardens.