Dun Skeig, vitrified fort

Climbing up to Dun Skeig from near Tarbert, you're hauling yourself up a proper hillside to reach what's left of an Iron Age fort - basically a stone structure that's been vitrified, meaning the rocks were heated so intensely they melted together into a glassy mass. It's genuinely odd to run your hands over, almost like someone's taken regular stone and turned it into something between glass and slag.

What you get is less dramatic ruin and more archaeological puzzle. The vitrification process suggests this place went down fighting - or at least burned extremely hot - and the remains are scattered across the hilltop. There's no visitor centre, no interpretation boards really worth reading. You're essentially scrambling about on a hillside looking at ancient rubble, which sounds underwhelming until you remember you're literally standing on top of a 2,500-year-old defensive structure.

Historically minded walkers will find this rewarding. Kids might get bored after twenty minutes unless they're into climbing and scrambling. The real draw is the walk itself - the views back down towards Tarbert and Loch Fyne are genuinely lovely, and if you're basing yourself at Port Ban Holiday Park just up the road, it's a satisfying half-day excursion that doesn't require specialist gear or permits.

Allow a couple of hours return trip. Go on a clear day - mist rolls in fast here and the rocky ground gets slippery. Free to visit, of course. It's the kind of place that sticks with you precisely because it demands a bit of effort.