The crumbling ruins of this craggy castle dominate the Bay of Sinclair. First called Girnigoe, it was built in the late 15C by William Sinclair, 2nd earl of Caithness, on the section closest to the headland, where you can see a rather scary dungeon. To the left, beyond a moat, are the buildings and ramparts which date from the early 17C. Even though the Sinclair clan was authorised to call their home Sinclair Castle, everyone continued to call it Girnigoe.