Porth yr Helig Cave

Getting to this cave requires a proper scramble down rocky slopes near Penmaenmawr, and frankly, it's only worth the effort if you're genuinely keen on coastal geology or fancy yourself a bit of an explorer. The cave sits in the limestone cliffs between Llandudno and Bangor, accessible at low tide through what feels like a mini adventure course of slippery rocks and seaweed.

Inside, you'll find a surprisingly spacious chamber that extends back into the cliff face. Local legend claims it was once used by smugglers, though there's precious little evidence beyond the romantic notion. The real appeal lies in the dramatic coastal setting and the satisfaction of reaching somewhere most tourists never bother with.

Families with young children should give this one a miss - the approach is genuinely tricky and potentially dangerous in wet conditions. Teenagers who don't mind getting their trainers soaked might find it exciting, but check tide times religiously before setting off. The cave can flood completely at high tide, leaving you with a very uncomfortable wait or a risky retreat.

Staying at nearby parks like Hafan y Gogarth or Aberconwy Resort puts you within easy striking distance, though you'll want to combine this with other coastal walks to make the trip worthwhile. Twenty minutes inside the cave is plenty for most people.