All along the Irish coastline you will see the Martello Towers. They are small round towers with almost flat roofs. They were designed and built as lookout posts during the Napoleonic Wars. Were an invading ship to be spotted by one of the lookouts in the tower, they would make his way to the roof of the tower and set fire to a bundle of wood.

This signal would eventually be seen by the next tower location, who in turn would do the same until all the towers along the coast would be notified of an approaching unidentified vessel.

James Joyce lived in a Martello Tower at Sandycove