National Trust - Cadbury Camp

Iron Age hill fort near Bristol that's genuinely worth the scramble up. You're looking at steep earthwork ramparts - seriously chunky ones - that date back around 2,500 years, and the views across Somerset from the top make the climb entirely worthwhile. The site's been worked over by later inhabitants too, including medieval folk, so there's proper archaeological interest if you're that way inclined.

The walk up takes maybe ten minutes from the car park, but it's no gentle stroll - the gradient's proper sharp in places. Once you're up there, the whole defensive setup makes sudden sense. You can trace the original layout of the fort clearly, which isn't always true of these Iron Age sites. Local history types will spend a good hour poking around and reading the landscape. Families with reasonably fit kids will find it engaging for an hour or so, though there's not much to actually "do" in the conventional sense - this is about standing around looking impressed at ancient earthworks and the countryside beyond.

It's free to visit and accessible from the car park, which is helpful. Summer's obviously better than winter when the slopes turn into mud slides. If you're staying at Somerset Glamping nearby, it's an easy add-on to a longer walk in the area. Not a destination in itself, but a cracking spot to understand how people defended themselves two and a half thousand years ago.