Twll Du

The walk up to Twll Du - a natural cave opening high on the mountainside near Caernarfon - rewards you with views that stretch across Snowdonia in one direction and down the Llanberis Pass in the other. It's a proper hike, mind you. You're looking at a good hour or so of climbing through moorland and rocky terrain to reach the cave itself, which sits at around 2,000 feet.

Once you're there, the cave mouth is modest - you can peer inside but it's not some vast cathedral of rock. What makes it worth the effort is the vantage point. On a clear day you can see Snowdon itself, and the scale of the surrounding peaks becomes genuinely impressive when you're standing up there rather than driving past them.

This is strictly for walkers with decent fitness and proper boots. Families with young kids will struggle unless they're the hiking type already. Weather changes fast up here, so don't attempt it in cloud or rain - you'll see nothing and the descent becomes genuinely sketchy.

The location makes it ideal if you're camping at Llyn Gwynant or Llanberis Touring Park. It's a solid day out combining the walk with exploring Caernarfon itself afterward. Allow a full morning or early afternoon, bring water, and don't go in poor visibility. It's not a casual stroll, but if you want to feel like you've actually earned a viewpoint rather than just pulled into a car park, Twll Du delivers.