The Cliffs of Moher are the Atlantic edge of Ireland, a wall of dark rock fourteen kilometres long and up to 214 metres high on the coast of County Clare, walked along the top with the sea breaking at the foot and thirty thousand pairs of seabirds nesting on the ledges below. The rock is layered shale and sandstone laid down as the mud of a river delta 320 million years ago, and the flagstone underfoot carries the burrows and trails of soft-bodied animals pressed into that mud, often the only record they left. A paved, walled path runs about a kilometre north from the visitor centre to O'Brien's Tower, a stone lookout put up in 1835 by Cornelius O'Brien, a landlord who traced his family to Brian Ború, the High King of Ireland, who built the tower so visitors could see the view in safety; from its top the cliffs run south in a line of headlands to Hag's Head, and the Aran Islands lie out in the bay. Beyond the walls a rougher path follows the cliff edge for kilometres in both directions.
From late spring the ledges fill. Guillemots, razorbills and kittiwakes crowd the rock, and on Goat Island, a grassy sea stack below the first viewing platform, nests the largest mainland colony of puffins in Ireland, seen from above with their orange feet and beaks against the green. Boats from Doolin run along the foot of the cliffs, where the wall is at its tallest and the birds are at eye level. The cliffs were the wall the heroes scale in The Princess Bride, renamed the Cliffs of Insanity. The wind is constant and the weather comes in off the Atlantic in minutes, so the same view goes from grey to gold and back in an afternoon; at sunset the rock turns copper and the light lies along the whole wall. The Cliffs of Moher are where Ireland stops, and the birds live on the last few metres of it.