St Nessan founded a monastery on Ireland's Eye off the coast of Dublin in the sixth century, and today the remains of an eighth century church can still be seen.
In the early 19th century a Martello tower was built to defend against attacks from France.
The island, now a bird sanctuary, has a rugged coast with a free standing rock formation known as 'The Stack'. Large numbers of guillemots, terns, gannets, razorbills, cormorants and puffins nest around the shore.