Did the Irish giant, Finn McCool, build this bridge at one time linking Ireland to Scotland? So goes a popular legend associated with the Giant’s Causeway. In any case, it’s a spectacular natural wonder of the world, and the only UNESCO World Heritage site in Northern Ireland. It’s composed of over 40,000 basalt columns that interlock, starting at the foot of the cliffs and disappearing out in the sea. The stones are generally shaped like hexagons and range in size and height. There’s a visitors center and well marked trails that explore the area and give different views of this amazing natural phenomenon.