Corkscrew Cave

Standing at the entrance, you'd be forgiven for wondering if this is really worth the scramble. Corkscrew Cave winds its way deep into the limestone cliffs near Llandudno, living up to its name with a series of tight, spiralling passages that'll test your nerve and your knees. The cave system requires proper caving gear and experience - this isn't a casual family outing.

Proper cavers will find the challenge rewarding, with some decent formations once you've navigated the trickier sections. The limestone here is old and well-developed, creating chambers that open up unexpectedly after the constricted entrance passages. Local caving groups know it well, though it's not as famous as some of the bigger systems further south.

Families staying at nearby parks like Hafan y Gogarth or Aberconwy Resort should look elsewhere for their underground thrills - this one demands experience and isn't suitable for children. The approach walk is straightforward enough from Conwy, but once you're at the cave mouth, it's serious business. If you're not already an experienced caver with proper kit, give it a miss and head to one of the show caves instead. Those who do tackle it will find a proper workout and some decent geology, but it's very much for the hardcore crowd only.