Poll na bPéist or the Wormhole as it is otherwise known is a striking natural rectangular shaped pool at the bottom of the cliffs, south of Dún Aonghasa. It gets it name from ‘péist’ which is the reptilian sea monster from Gaelic folklore.
The unusual rock formation also has underground channels which link up to the sea. The water rushes into the Wormhole through an underground cave, or when the tide is high, spills over and fills it up from above.
Since 2012, the wormhole has been used as a venue for the popular Red Bull Cliff Diving World Series.
My theory is that this may be the origin of the stones used to build Stonehenge or similar structures. Due to the way the stone fractures it would not have been too difficult for people to crack the stone to desired sizes and query them out to build with. Now the hard part would be how they transported them. But we know that the stones came from somewhere and were moved so here is a possible origin. Also there may be other such places that have been lost over time that could be similar and monuments build with these stones lost as well.