Belfast Castle Visitors Centre

They've labelled this Belfast Castle Visitors Centre rather than Belfast Castle because there's no real 'castle' to explore: the interior facilities are reserved for weddings and such functions, so don't let the kids go expecting turrets and spiral staircases. However, the other features here more than make up for it, with plenty to do if you've got good weather.

The Castle and its grounds are within Cave Hill Country Park, so you've got plenty of space to explore and plenty of things to look for, including the local landmark Napoleon's Nose!