Dunstaffnage Castle in Argyll and Bute

You're standing at Dunstaffnage Castle, a few kilometres north of Oban. First, look at what it's built on: a huge rock of conglomerate, a kind of natural concrete made of pebbles and sand. The walls seem to grow straight out of it. Together with that rock they rise as high as eighteen metres, and the shape of the rock dictated the shape of the whole castle. The sea surrounds it on three sides. Whoever held this place controlled the way into Loch Etive and the route inland.