According to legend the volcanic feature was built by the Irish giant Fionn Mac Cumhaill.
After being challenged to a fight by the Scottish giant Benandonner, Fionn constructed the Causeway over the sea to reach him.
Actually the same immense lava flow that created the causeway also formed the basalt columns at Fingal’s Cave on the Scottish Island of Staffa, which may have influenced the story.
The Causeway is made up of approximately 40,000 basalt columns formed 50-60 million years ago from a massive eruption of lava as it cooled and cracked which formed a pattern.
Archaeology Study Unit 