Howth Head Lighthouse
This is another shot from my recent expedition by sea from Dun Laoghaire to Howth (& back).
Besides being an interesting and important lighthouse in relation to the Port of Dublin - it's the northern end of Dublin Bay - the lighthouse is an important global centre of software development! +[D4H] Technologies, who develop software supporting emergency response organisations all over the world, are headquartered in the building somewhere.