Formerly the seat of British power in Ireland, and efficiently infiltrated by spies during the Michael Collins era, this isn't really a castle - no moat, no drawbridge to lower against invading hordes, no turrets from which to pour boiling oil - more a collection of 18th-century administrative buildings, albeit very fine ones, built on a medieval plan of two courtyards.
A figure of Justice stands over the main entrance, dating from the time of British rule, and is something of a sardonic joke - she stands with her back to the city, wears no blindfold and her scales tilt when filled with water. In 1922 this is where the last Lord Lieutenant of Ireland, FitzAlan, symbolically handed over the castle to Michael Collins, who kept him waiting seven minutes.
When FitzAlan complained, Collins retorted, 'We've been waiting over 700 years, you can have the extra seven minutes.' The Castle's current role is to provide venues for grand diplomatic or state functions, and occasional artistic performances, such as concert recitals. The interior, including beautiful State Rooms, is operated on a pay-per-view basis, but you can wander freely around the exterior.