Bruce's Cave on Rathlin Island

http://www.andymcinroy.com/5port6b.htm

One of the locations I used in The Black Swans is Bruce's Cave on Rathlin Island off the coast of Ireland. The cave is famous because of local lore that this is where Robert the Bruce of Scotland and his men hid when pursued by the armies of England.
While hiding there and in despair over his defeat, he noticed a spider trying to climb up the wall. The spider kept falling back, but continued to try which encouraged him to go back to Scotland and eventually defeat the English at Bannockburn.

Sea Caves on Rathlin Island

Great Sea Caves of Antrim - Bruce's cave, Rathlin Island. This is the cave that Taisie lands in near the end of the book. It is called Bruce's Cave because Robert the Bruce supposedly hid out here while fleeing the English. He saw a spider struggling to make it's way up the wall and decided it was an omen for his own struggle. He went on to defeat the English at Bannockburn.