Dun Aengus, Inis Mór, Aran Islands, Co. GalwayThree thousand years ago, somebody looked at a hundred metre cliff dropping into the Atlantic and thought: that's my back wall. Dn Aonghasa has fascinated me since childhood, and that single design decision is the reason. A semicircular fort perched at the very limit of habitable land, using a sheer limestone drop as its final defence. I got the drone up on a rough evening when the cloud was thick and low but tearing apart to the west. Late sun pushed