If you happen to be going round a roundabout on the outskirts of Dun Laoghaire and suddenly see a castle, chances are this is it :-) It surprises me every time!
It was built in the 13th century by the cistercian monks, after whom the village of Monkstown is named, to defend against raids by the Wicklow Clans. The ruins consist of an impressive gate-house and the remains of a Keep. Originally the castle would have been an imposing structure with three towers and a large house with six chimneys.
After the Dissolution of the Monasteries in 1539, Sir John Travers was given control of the castle. Until the development of Dun Laoghaire in the late 18th-early 19th centuries, Monkstown Castle would have been considered the chief residence of the area, though thats hard to see now! The estate was broken up in the 18th century and from the 1780's the castle fell into decay and eventually became the ruin you see today.
Every child should have an old cannon to play with :-)
This one has an interesting history, being one of hundreds of Russian cannon captured in the Crimean war (1853-56) and taken home by British forces. The War office distributed the guns to any town that asked for one and so Dun Laoghaire ended up with this 24 pounder gun. It was only set up in its current location in 1974 and as far as I know has not been fired since the Russians had it!
As one of the major recruiting grounds for the British Army at the time, a large number of Irish fought and died in the Crimea. By some estimates up to a third of the British forces there were in fact Irish.
The Commissioners for Irish lights have responsibility for maintaining all of the lighthouses off the Irish coast. At this point these have all been automated and the Commissioners use the Granuaile tender vessel to service them. Its often to be seen in and around Dun Laoghaire harbour, where the Commissioners are now builidng their new headquarters (their technical facilities have been there for many years)