Napoleonic watch tower, Slieve League, Co. Donegal

Most people turn back at Bunglas. The main cliffs at Slieve League are extraordinary, and I understand the impulse to stop there. But if you keep walking east, you reach this headland, and everything changes.

The Napoleonic watch tower sits on the summit like it was grown from the rock itself. Same design you'll find all the way down the west coast, from Donegal to Kerry. Same proportions, same stone, same purpose. I've stood beside these towers in half a dozen counties now, and every time I get the feeling that a single tower has been quietly following me from headland to headland.

I made this photograph about thirty minutes before sunset. The sun was low enough to rake across the west-facing cliff faces, picking out every fold and fracture in the quartzite. From above, the scale becomes clear. That thin neck of rock connecting the stack to the mainland. The Atlantic on three sides. The tower looks both purposeful and absurd up there. Whoever built it chose a position with complete command of the sea approaches, but getting materials to that point must have been miserable work.

The sea was calm that evening. Not a breath of wind, which is rare enough at Bunglas that it felt like a gift. I think about the soldiers who manned these towers. Posted to a rock in Donegal, watching for a French fleet that mostly never came. The views would have been wasted on them!