Dunselma

The ruins of Dunselma sit on a headland near Dunoon, commanding views across the Firth of Clyde. What remains is largely fragmentary - tumbled stone and overgrown foundations rather than the kind of castle you can actually walk around - but that's part of its appeal if you're into the rawer side of Scottish archaeology.

This was a medieval stronghold, though pinning down exactly when it was built or destroyed is harder than it should be. The ruins themselves don't tell much of a story to the untrained eye, which is why it works best as a supplement to a proper castle visit elsewhere, not a destination in itself. You'll spend twenty minutes here at most, photographing the stones and taking in the water views.

Historically-minded visitors will get more from it than families with young kids, and even then only if you're already exploring the Dunoon area. The walk to the site can be muddy and overgrown depending on the season, so proper footwear matters.

If you're based at one of the nearby parks - Hunters Quay is closest at just over a mile away - it's worth a quick detour on a dry afternoon. Combine it with a proper look around Dunoon town and you've got a decent half-day. But don't plan your entire holiday around it. The castle's appeal lies in its fragility and neglect, not in any grand structure or interpretation. That's either fascinating or underwhelming depending on what you're after.