• Giant’s Causeway and Causeway Coast

Visit: 25th June 2016


Giant’s Causeway is Northern Ireland’s only World Heritage Site, and one of just three on the island of Ireland. I had never been to this constituent country of the UK, and given Ryanair’s offer of £25 return flights from Gatwick to Belfast I booked us a day trip.


It is necessary to hire a car to reach the Causeway Coast, which is located at the northern tip of the island. This came in at only £16 for the day, keeping the costs nice and low. It was about an hour’s drive from Belfast Aldergrove airport on a typical summer’s day of mild temperatures and a heavy grey sky.


The visitor’s centre is new and blends well into the terrain. We didn’t go inside because entry is bundled with car parking and the car park was full. We were able to park in a miniature railway car park just a few minutes down the road, which was significantly cheaper (the official car park is £9 per person, whereas the one we used is something like £6 per car).


The Causeway Coast is free to enter and open to the public like any coastal path. It takes ten minutes to descend from the visitor centre to the Giant’s Causeway, which was pretty busy with American tourists. It seems as if it is more famous in America than in Britain, judging by the range of accents we heard.


The famous hexagonal pillars are the product of an ancient volcanic eruption. Molten basalt was forced up through chalk, and as it cooled and contracted it cracked into hexagons, like drying mud. The reason hexagons formed is because they are the most efficient shapes that tessellate (efficient in the sense of having the smallest ratio of edge length to surface area). The only other regular shapes that tessellate are squares and triangles. The utility of hexagonal tiling is more intuitive if you think of honeycombs, where bees use the shape to provide as strong and large a structure as possible for the least amount of wax required.


Giant’s Causeway is far from unique in having these hexagonal columns of volcanic rock. In fact you can find them all over the place, but particularly around what might be termed the ‘Atlantic rim’ – ie. the west coast of the Europe and the east coast of North America. Here in County Antrim they are the most striking, but the reason you will find them elsewhere is because they are the product of the same volcanic eruption, back when the continents were all as one under the name Pangaea. They have slowly but surely been forced apart by continental drift at a rate of 2.5 cm per year so that Ireland and America are now some 3,000 miles apart. The epicentre is known today as the Mid-Atlantic Ridge, and it is still a point of great geological activity far beneath the waves. The ridge also runs through Iceland, giving that country its unique geology and giving rise to the WHS, Thingvellir National Park.


The Giant’s Causeway UNESCO inscription does not just cover the famous Causeway but also the coast more generally for several miles to its east. We walked along the coastal path until reaching the edge of the inscribed zone, where it was very quiet indeed. Headland after headland jut out into the Atlantic, many boasting basalt columns exposed from the side.


We had a traditional Irish lunch of steak pie and a pint of stout before driving south back towards Belfast. There was time to stop off at Loch Neagh, which is the UK’s largest lake by area, at 150 square miles. According to Irish folklore the lake was formed when a local giant, Finn MacCool, scooped up a handful of earth to hurl at a rival in Scotland, but his throw wasn’t long enough and it ended up landing in the Irish Sea to form the Isle of Man. This same giant is said to have begun building Giant’s Causeway as a way of crossing the sea to get at the other giant, named Benandonner, in Scotland.


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