Fourteen Swallets #4

The four natural sinkholes that make up Fourteen Swallets aren't your typical tourist cave experience - they're proper geological features where streams disappear underground into the Denbighshire limestone. You won't find gift shops or guided tours here. What you get instead is the chance to scramble around a landscape that actually looks like something, rather than a manicured attraction.

The walk itself is fairly straightforward, though you'll want decent boots. The main appeal is seeing how water carves through rock over millennia - watching a small stream vanish into darkness never gets old. Serious cavers use these sites; casual visitors find them interesting enough for an hour or so, particularly if you've got kids who enjoy poking about in the outdoors.

It's not a day-long activity on its own, but it pairs well with walking in the surrounding Clwydian Range. Ruthin is only a few miles south and makes a sensible base - the town itself has decent pubs and shops. If you're camping at Clwydian Glamping Pods and Campsite, this is the sort of morning diversion that justifies the drive up into the hills.

There's no charge and no formal opening hours, which means you can visit whenever. Wet weather actually makes them more interesting, oddly enough - you'll see more water movement. Allow ninety minutes including the walk, though determined walkers and cave enthusiasts could spend longer exploring the surrounding terrain.