Threave Castle

The River Dee winds right past this 14th-century fortress, and that's half the appeal - you're looking at a proper medieval stronghold reflected in water, which makes for decent photos even if you're not a castle obsessive. Threave sits on an island, so there's a small boat crossing involved, which adds a bit of theatre to the visit. The castle itself is a four-storey tower built by the Black Douglases, one of those powerful families who basically ran this corner of Scotland before the crown got tired of their ambitions.

The interior isn't lavishly furnished - it's more about standing in thick-walled rooms and imagining medieval life happening around you. History buffs will appreciate the defensive design and the layers of power struggle written into its stones. Families with kids usually enjoy the boat trip more than the castle itself, to be honest. Budget forty-five minutes to an hour including the crossing.

It's free to visit and managed by Historic Environment Scotland. The nearest facilities are in Castle Douglas, which sits about three miles away and has decent cafes if you need lunch. If you're basing yourself at one of the local caravan parks - Loch Ken Holiday Park is nearest at just under six miles - Threave makes for an easy afternoon jaunt. Pair it with a walk along the Dee or a visit to the surrounding countryside rather than expecting it to anchor a full day. Go on a clear day if you can; grey skies don't do the river views any favours.