The Giants Causeway
According the local legend of this site on the north east coast of Ireland, Finn McCool built the causeway to Scotland to challenge the Scottish giant called Benandonner. When the latter started to walk across it Finn noticed the size of the giant, and realised Benandonner was far larger than himself. So he went back to his wife. When Benandonner arrived at the McCool homestead, he was met by Finn's wife and a baby, and Finn was away hunting. He left and then Finn revealed himself to be the baby, after disguising himself. After this he grabbed a piece of land out of the ground and flung it into the sea to break the causeway. This caused Lough Neagh to form from the missing land, and the land that was thrown became the Isle Of Mann.