The Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption during the Paleogene Period, around 50 to 60 million years ago. According to legend, the columns are the remains of a causeway built by a giant.
Time for more "As seen on" Game of Thrones. The Dunluce Castle represents House of Greyjoy, ruler of the Iron Islands. This castle is a now-ruined castle on the edge of a basalt built in the late middle ages and 17th century.