Giant's Causeway in Ireland has 60 million-year-old basalt columns

The Giant's Causeway lies at the foot of the basalt cliffs along the sea coast on the edge of the Antrim plateau in Northern Ireland. It's made up of some 40,000 interlocking black basalt columns believed to be caused by volcanic activity during the Tertiary, some 50–60 million years ago. It was declared a UNESCO World Heritage Site in 1986.