5. Hillsborough Castle, Belfast
This gorgeous 18th century Georgian estate, Hillsborough Castle, is the official residence of the British Royal Family on their visits to Northern Ireland. Take a walk through the State Rooms, the majestic Throne Room and Lady Grey’s Sitting Room. Make sure to check out the mahogany secretaire with a bookcase top, said to have been made for the Titanic’s sister ship, the Britannic. Outside, the ornamental grounds, woodlands and carefully trimmed lawns are perfect for a stroll.