It looks like something from Downton Abbey – only bigger and grander. Belfast Castle, just outside the city, was built in 1870 and housed Sir Arthur Chichester, former Lord Deputy of Ireland. Tour the endless rooms and winding staircases inside. There’s a visitor’s centre to learn more, a shop for souvenirs and an outdoor café for afternoon tea with fabulous city views. Keep walking up and you’ll reach Cave Hill mountain walk with its five mysterious caves. It’s said Jonathan Swift’s Gulliver’s Travels was based on this magical place.