This is a joy for anyone interested in archaeology or history. Dublin Castle was built in the 13th century on top of the foundations of a Viking structure.
The castle served as a military fortress, prison, court of law and the core of British administration in Ireland until 1922.
It's now used for state functions and government conferences. Guided tours are available.
While walking the grounds don't forget to pay a visit the the Chester Beatty Library.
With free admission it is a must-see on any Dublin visitor's itinerary. As the only museum in Ireland to win 'European Museum of the Year' and rated consistently in the top 5 of TripAdvisor’s list of ‘Top things to do in Dublin', the library's rich collections from countries across Asia, the Middle East, North Africa and Europe open a window on the artistic treasures of the great cultures and religions of the world.