St Catherine's Castle

You'll spot St Catherine's Castle from miles away - that squat, circular fortress sits right on the headland above Polruan like a stone sentinel watching over the Fowey estuary. Built in the 1530s to protect the harbour from French raiders, it's the kind of place that looks impressive from a distance and feels genuinely atmospheric when you actually walk up to it.

The castle itself is small - a proper ruined fort rather than the dramatic keeps you might be expecting. What makes it worth the visit is the walk there and the views from the top. The path climbs steeply from Polruan (give yourself twenty minutes unless you're very unfit), and once you're inside the crumbling walls, you get that rare feeling of being somewhere genuinely old and strategically important. The estuary spreads out below you, and on a clear day the light hits the water just right.

This is best for walkers and history types rather than younger children - there's not much to actually do once you're there, just wander the ruins and absorb the atmosphere. Allow an hour maximum. Free to visit, and no specific opening hours to worry about.

If you're staying at Par Sands or Tremeer Farm, both just a couple of miles away, this makes an easy afternoon outing to break up the holiday routine. It's the sort of place that takes fifteen minutes to see properly but lingers in your memory longer than the big tourist attractions do.