Saltcoat Castle (remains)

The ruins of Saltcoat Castle sit on a grassy headland near East Lothian, looking out toward the Firth of Forth. What remains is modest - crumbling stone walls and foundations rather than anything you'd call dramatic - but the setting makes the short detour worthwhile. Built sometime in the 1600s, it was never a fortress of grand proportions; more a fortified house for someone with money and a taste for coastal views.

You can wander around freely, which is the best way to explore somewhere this fragmented. The coastal walk to reach it is better than the ruins themselves, truth be told. The path takes you past farmland and scrubby vegetation, with proper views opening up as you approach. On a clear day you can see across to Fife. The castle itself is interesting if you're into 17th-century domestic architecture and defensive design, but it won't keep you occupied for hours.

History enthusiasts will find it worthwhile; families with small children might find the exposed stonework and uneven ground a bit fiddly. Allow 30-45 minutes including the walk. There's no visitor centre, no café, nothing at all - just the ruins and the landscape. It's free to visit and accessible year-round, though winter can make the ground soggy.

If you're staying at Haven Seton Sands Holiday Village just down the coast, Saltcoat slots neatly into a morning exploring the local beaches and headlands. Don't make it your main event, but absolutely worth the short walk if you're in the area.