The Giant’s Causeway has been a UNESCO World Heritage site since 1986 and part of a national nature reserve since 1987. It’s famous for its distinctive rock formations - basalt columns which tessellate in order to create the effect of a tiled path. The basalt shapes, most of which are hexagons, formed as a result of volcanic eruptions 50 to 60 million years ago, during the Paleocene, when molten basalt cooled and contracted, cracking in a similar way to dried mud. Originally the Causeway was part of the Thulean Plateau, which stretched between Northern Ireland, Scotland, Norway, Iceland, eastern Greenland, and several islands in the North Atlantic. As the North Atlantic Ocean opened up and the modern continents began to form, the plateau was broken up. In addition to the Giant’s Causeway, there are surviving elements visible in Greenland, Fingal’s Cave in Staff, Scotland, and other locations in the UK.