Dyke Hills Iron-Age Oppidum

Two thousand years ago, someone built serious earthwork defences around this stretch of land near Oxford, and they're still there if you know where to look. Dyke Hills is an Iron-Age oppidum - a fortified settlement from roughly 100 BC - and what you get is a walk through countryside dotted with the remains of banks and ditches that once ringed a settlement of some importance.

It's not dramatic. You won't find reconstructed roundhouses or interpretation panels spelling everything out. What you will find is a proper landscape puzzle - low earthwork ridges that become obvious once someone points them out, but easy to miss if you're just strolling past. That's partly the appeal. This is archaeology for people who like to think rather than be told.

Walkers and history types will get far more from it than families with young children - there's no "attraction" in the theme-park sense, just the bones of a settlement spread across fields. Allow an hour to wander and take it in, longer if you're the sort to sit on a stile and read up beforehand. It's genuinely free, being essentially unmarked landscape.

Oxford's close by if you want proper facilities and museums to compare notes afterwards. Benson Waterfront and Bridge Villa Camping sit within easy striking distance if you're basing yourself at one of the local parks. Combine it with a walk along the Thames Path - the oppidum overlooks the river - and you've got yourself a solid half-day out.