Dublin Castle
Seven centuries of Irish history packed into one remarkable castle complex.
Dublin Castle isn't really a castle in the fairy-tale sense — it's a sprawling medieval-to-Georgian complex that served as the administrative heart of British rule in Ireland for over 700 years. Built on the site of a Viking settlement, it was the seat of the Lord Lieutenant of Ireland until 1922, when the keys were ceremonially handed to Michael Collins and Irish independence began. Today it functions as a state venue still used for presidential inaugurations and EU summits, while being open to visitors who want to understand how Ireland was governed — and eventually liberated from — one of history's most powerful empires.
Visitors explore the State Apartments, which are genuinely spectacular — gilded rooms, Waterford crystal chandeliers, and the Throne Room where British monarchs once held court. The Undercroft is particularly striking: descend beneath the cobblestoned Upper Yard and you'll find the excavated remains of the original Viking-era defensive wall and the old moat, still visibly intact. The Chapel Royal, completed in 1814, is a beautiful piece of Gothic Revival architecture with intricate limestone carvings and an ornate interior. Guided tours are available and add real depth to what you're seeing.
The castle sits right in the medieval core of Dublin, steps from Dame Street and the Cultural Quarter. Tours run regularly and the last admission is around 5:15pm — arrive by 4:30pm at the latest if you want to do it properly. The Revenue Museum in the castle grounds is free and often overlooked, covering Irish customs and tax history in a surprisingly engaging way. On State occasions parts of the castle may close without much warning, so it's worth checking ahead if you have a specific date in mind.