Giant's Causeway

The Giant's Causeway is an area of about 40,000 interlocking polygonal basalt columns on the north coast of County Antrim, Northern Ireland, formed by an ancient volcanic fissure eruption around 50 to 60 million years ago during the Paleogene period. As the extensive lava flow cooled, it contracted and cracked into predominantly hexagonal columns, some standing up to 12 meters tall, with the solidified lava forming a stepped, causeway-like platform running from the cliff foot into the sea. It is one of the type localities cited worldwide for columnar basalt and is linked in Irish legend to the giant Finn McCool, said to have built the causeway to reach Scotland. It became Northern Ireland's first UNESCO World Heritage Site in 1986.