Fourteen Swallets #3

Three natural sinkholes in the Denbighshire hills, just a short drive from Ruthin - proper geological drama if you know what you're looking at. The Fourteen Swallets are where water disappears underground into limestone, creating these dark funnel-shaped openings that locals have been pointing out for centuries.

You won't need climbing gear or a guide. Walk in from the nearby lane and you can stand at the rim looking down into the void - it's unsettling in the best way. The third swallet is the most impressive, a proper gaping hole that swallows a stream. Bring a torch if you want to peer deeper, but most visitors are happy with the surface views. The whole thing takes twenty minutes, maybe half an hour if you're photographing or just standing about thinking about water physics.

This is walkers' territory, really. Families with curious kids will get something out of it - there's an element of mild danger that appeals to young minds - but you need to be comfortable with rough ground and liable to get muddy. History enthusiasts might appreciate the Tudor-era maps that reference these features, proof they've been known about for ages.

Free, naturally. No facilities, no parking area as such. Best attempted after dry weather so you're not sliding about. If you're staying at Clwydian Glamping Pods nearby, it's an easy morning walk before breakfast. Combine it with Ruthin's market town wandering and you've got a decent half-day sorted.