Twll y Gesail

The walk up to Twll y Gesail rewards you with something genuinely unusual - a natural arch carved into the mountainside, proper dramatic stuff. You're essentially walking through a hole in the peak, which sounds daft until you're actually standing underneath it wondering how on earth geology managed that. The nearest town is Dolgellau, about an hour's walk away if you're coming from the valley, though most people drive up and park at one of the lower trailheads.

It's a solid two to three hour round trip depending on your pace and the weather. The terrain gets steep and rocky near the summit, so this isn't a casual stroll - bring proper boots and check conditions before you go. Winter scrambles can be dicey. In decent weather though, the views across Gwynedd are proper stunning, and the arch itself feels special because it's not overrun with tourists the way some peaks are.

Families with older kids (10 plus) will manage fine if they're used to hill walking. Younger ones might find the final push tedious. This is really one for walkers who want something a bit different from your standard peak baggers' hill. History types will appreciate the geological story, but you're not getting remains of anything archaeological here - just nature doing its thing.

If you're based at Llwyn yr Helm Caravan and Camping Park down the road, this makes a cracking day out. The peak is accessible year-round, though spring and early autumn tend to offer the clearest views. Free to climb, no facilities at the top - bring water.