P9 [Christmas Swallet]

You'll find Christmas Swallet tucked into the limestone hills above Hope Valley, a proper sinkhole that swallows a stream and disappears underground. It's exactly what it sounds like - water vanishes into a cave mouth and you can follow it in, at least for a bit, depending on water levels and your nerve.

This isn't a tourist cave with lit passages and guided tours. It's raw caving country. The entrance is accessible enough that families keen on a bit of adventure can peer in and get a sense of the underground system, but anything more serious needs proper gear and experience. The real appeal is the drama of it - watching water actually drain into the earth, the geological story written in the rock face.

Walkers will appreciate the effort. It's a decent trek from Hope Valley and the landscape around it tells you everything about how the Peak District's water systems work. Geology enthusiasts will be in their element. Young kids might find the entrance impressive but won't stay long without proper kit and supervision.

If you're camping nearby - Castleton Caravan and Motorhome Club is only 2.8 miles away and gets solid reviews - Christmas Swallet makes an interesting half-day mission combined with walks in the broader Hope Valley area. Best visited after rain when the water flow is obvious, though that also means muddier approaches. Spring or autumn beats summer crowds, and you'll have clearer views without the undergrowth.