Harry's Walls

Harry's Walls are the remains of an unfinished artillery castle situated on a hilltop to the north-east of Hugh Town on St Mary's, the largest of the Isles of Scilly in Cornwall.

The fortification was begun in 1551 as part of a major phase of fortification on the Isles of Scilly, undertaken to counter threats from the French. It was left unfinished because the site was recognised to be unsuitable.