"A short walk from Trinity College, Dublin Castle was built in the 13th century on the site of a Viking settlement. Its medieval tower, with walls up to nearly 16 feet thick, was constructed mainly during the reign of Henry III, King of England and Lord of Ireland. Today, the castle is a government complex as well as a tourist attraction, open daily for self-guided visits and guided tours of the chapel royal, state apartments, undercroft, and heritage center. The Castle Gardens, enclosed by wrought-iron gates with Celtic-inspired spirals, are also popular with visitors." - Travel + Leisure Editors