The Giant's Causeway is one of the most extraordinary natural formations on earth — a vast expanse of around 40,000 interlocking basalt columns that emerge from the sea at the foot of the Antrim cliffs like the remnants of some impossible ancient construction. A UNESCO World Heritage Site since 1986 and Northern Ireland's most visited tourist attraction, it draws over one million visitors a year, and yet it still manages to feel genuinely otherworldly when you first set eyes on it.

The columns were formed around 60 million years ago when a massive volcanic eruption sent molten basalt flowing across the landscape. As the lava cooled and contracted, it cracked into the distinctive hexagonal columns — most are six-sided, though some have four, five, seven, or eight sides. The tallest columns in the Grand Causeway area stand around 12 metres high. The same geological event also created Fingal's Cave on the Scottish island of Staffa, which has an almost identical formation — the two sites are connected by the same ancient lava flow.

Irish mythology offers a more colourful explanation. According to legend, the giant Fionn mac Cumhaill (Finn McCool) built the causeway as a bridge to Scotland so he could fight his rival, the Scottish giant Benandonner. When Fionn saw how enormous Benandonner was, he fled home and his wife disguised him as a baby. When Benandonner arrived and saw the size of the 'baby', he concluded the father must be terrifyingly large, tore up the causeway in panic, and fled back to Scotland — leaving only the stumps on either side.

The Causeway Coast as a whole is one of the most dramatic stretches of coastline in Europe. The cliff path east of the causeway passes the ruins of Dunluce Castle — a medieval fortress perched on a sea stack so dramatically that part of its kitchen reportedly fell into the sea during a storm in 1639 — and continues to the famous Carrick-a-Rede rope bridge, a 20-metre span strung 30 metres above the sea that was originally erected by salmon fishermen. The entire Causeway Coastal Route from Belfast to Derry is one of the world's great coastal drives. If you're spending a night in Belfast before or after the coast, OX on Howard Street is one of the finest restaurants on the island of Ireland and well worth planning your evening around.

The National Trust visitor centre, opened in 2012, is built into the hillside and provides excellent context on both the geology and the mythology of the site. From the centre, a shuttle bus runs down to the causeway itself, or you can walk the cliff path down and back — the walk takes about 20 minutes each way and offers increasingly dramatic views as you descend. The site is at its most magical in the early morning before the crowds arrive, or in the golden light of a summer evening.