Brownsea Castle

You'll need a boat to reach this one, which is half the appeal. Brownsea Castle sits on its own island off the Dorset coast near Swanage, a Victorian fort built in the 1850s that looks properly dramatic rising from the water. The castle itself is small - honest about it - but the journey out and the views back across Poole Harbour make it worth the trip for anyone who's not after a quick tourist tick.

Inside, it's a working garrison fort with period rooms and displays that tell you something about 19th-century military life without being dull about it. Kids actually engage with the cannons and the fort's layout. The island around it is nature reserve land, so you get a decent walk in, spotting birds and taking in the shoreline. Allow a good two hours once you're there, longer if you're keen on photography.

Histor buffs will find it satisfying - there's real substance to the place, not just empty rooms. Families with younger children might find the boat journey the highlight, if we're being frank. The castle adds gravitas but it's compact.

Head out from Swanage and combine it with the nearby holiday parks - Ulwell Holiday Park and Swanage Bay View are both within easy reach and excellent bases for exploring the area. The castle isn't free and you'll need to arrange boat access through licensed operators, but it's the kind of outing that feels properly different from a standard day out. Worth doing once.