Belgic Oppidum. Ancient British town

You won't find much to look at on the ground here - that's the thing about Iron Age settlements. The Belgic Oppidum near St Albans is basically a patch of farmland where, two thousand years ago, a proper settlement once thrived. Ancient Britons dug ditches, built structures, and traded goods across what would become Hertfordshire. Today you're standing on the earthworks themselves, tracing the faint defensive lines with your eyes and trying to conjure what life looked like before the Romans arrived.

It's genuinely worth a detour if you're into British archaeology or Iron Age history - the kind of place that rewards imagination over instant gratification. Families might find it a bit underwhelming unless the kids are already keen on ancient history; there's no visitor centre, no interpretation boards to speak of, just the bones of the landscape. Allow half an hour or so, longer if you want to walk the full perimeter and soak up the countryside.

Free to visit, obviously. St Albans itself is only a short drive away and holds far more obvious attractions - the cathedral, the town itself - so you could easily combine this with a proper day out. The nearby caravan parks (Cherry Green Trees gets particularly good reviews) make a solid base if you're exploring Hertfordshire's archaeological side. Spring and early summer are best - the grass is manageable and you can actually see the ditch patterns without squinting through overgrown nettles.