Fair Head's columns are not basalt like the Giant's Causeway a few miles west. They are dolerite, a coarser-grained relative of basalt, and they form what geologists call a sill: a tabular sheet of molten rock that was injected horizontally between layers of older sedimentary rock and then cooled in place. The injection happened about sixty million years ago, in the Palaeogene era, when the North Atlantic was tearing open and the volcanic province that gave us the Giant's Causeway, Mull, and the Inner Hebrides was at its most violent. As the dolerite cooled, it cracked into hexagonal and pentagonal columns, the same physics that produced the Causeway, but here the columns are vertical, fifty to a hundred metres tall, and they form not steps but a wall.

To climbers, Fair Head is one of the great trad-climbing destinations of the world. 'Trad' means traditional: no pre-set bolts, no fixed protection, only what the climber places into cracks as they ascend, and removes after themselves. Fair Head's routes average over fifty metres, with many running up to a hundred. The cracks are perfectly proportioned for hand-jamming - inserting a clenched fist or open hand into the crack and using it as a wedge - and the friction is so aggressive that climbers tape their hands to prevent what is locally called Fair Head rash. The whole cliff is divided into named sectors. An Bealach Runda. Grey Man's Path. The Prow. Marconi's Cove. The Big Skin. Some sections are reached only by an intimidating ninety-metre abseil from in-situ stakes at the top. Once you are on the wall, there is no going back unless you climb.

Every year, on the first weekend of June, Mountaineering Ireland organises the Fair Head Climbing Meet. Climbers from across the British Isles and well beyond camp at the headland, climb together, and share the queue for the better-known routes. The American climber Alex Honnold, of Free Solo fame, came to Fair Head in June 2016 and flashed a route called The Dark Side at the E8 6c grade - a first-attempt ascent of one of the hardest routes on the wall. Local hero Ricky Bell, in 2015, free-soloed Long Runs the Fox at E9 6c in Murlough Bay, climbing without ropes the kind of route most climbers would not attempt with full protection. The combination of route quality, scale, and steep crack climbing has earned the headland a global reputation that the surrounding villages of north Antrim are only beginning to register.

If you visit Fair Head and never see a climber, the headland still rewards the trip. The McBride family farm has worked this land for over three centuries and gives access to walkers. The plateau on top is open moorland scattered with small lakes. In one of those lakes, the largest of them, sits a man-made island - an Iron Age crannog, built up from stones thousands of years ago and used as a defensible dwelling. Wild goats with shaggy white coats graze the cliff edges and occasionally pose for photographs against the basalt of Rathlin Island in the background. Murlough Bay, just east of the main cliffs, is a steep wooded gorge running down to the sea, with a small road that ends at a stone-built nineteenth-century cottage and one of the loneliest beaches in Northern Ireland.

Like much of the Antrim coast, Fair Head has had its turn in Game of Thrones. Two episodes of Season 7, The Queen's Justice and Eastwatch, used the headland as a location, the dolerite face standing in for various fictional cliffs of Westeros. The film crews come, the cameras roll, and the headland goes about its business. Climbers continue working out new routes. Goats continue cropping the heather. Most days you can stand on the clifftop and hear only the wind, the sea below, and - if you are lucky - the distant calling of a peregrine falcon, the fastest bird in the world, riding the updraft from the columns down to the boulder field. From the top edge, looking out, Rathlin Island sits clear in the middle distance, the Mull of Kintyre stretches across the channel to the northeast, and on a still afternoon you understand why the old Irish called this place the Great Cliff.