Crannog

The remains of an Iron Age dwelling sit submerged in the shallow water near Alexandria, waiting for you to piece together what life looked like two thousand years ago. A crannog was essentially a circular house built on an artificial island - early Scots weren't messing about when it came to home defence. What you'll actually see is a low stone platform in the loch, best viewed from the shore, though the full story only emerges if you're willing to do a bit of reading beforehand or chat to locals who know the site well.

This is one for archaeology enthusiasts rather than casual day-trippers. Kids might find it interesting for five minutes, but there's no visitor centre or interpretation boards to explain what you're looking at, so it works better as a stop-off if you're already walking the loch shore. The real appeal is standing there knowing someone built this, lived here, and chose to abandon it centuries before Romans turned up. That's properly moving if you're into that sort of thing.

Allow an hour if you're combining it with a walk around the water's edge. It's free to visit. The real draw is the location itself - Loch Lomond is spectacular, and staying at one of the holiday parks nearby (Stoneymollan, Loch Lomond Retreat, or Lomond Woods are all within walking distance) gives you a genuine reason to explore the loch properly rather than just drive past. Go on a clear day when the water's calm enough to see the structure clearly.