Rathlee Signal Tower, Co. Sligo
In response to the 1798 Irish Rebellion and the threat of invasion from the French during the Napoleonic wars, as many as 50 signal towers were built by the British at many remote coastal sites in Ireland from 1804 onwards. They were never designed to hold artillery, but were part of an optical telegraph system that involved each signalling station to be visible to its counterparts on each side. With the threat of invasion significantly diminished after the defeat of Napoleon at Waterloo in 1815, most of these stations were eventually abandoned to become ruins like this example at Rathlee.