Marchlyn Mawr

High up in the Snowdonia hills near Bangor, Marchlyn Mawr is a proper mountain lake that demands respect - and a decent pair of boots. This isn't some genteel lowland reservoir you can wander around in trainers. The water sits at over 1,600 feet, cradled by steep slopes that funnel wind down the valley with impressive force.

What you're looking at is a working water supply reservoir, so don't expect facilities or crowds. The appeal is raw: dark water reflecting grey Welsh sky, mountains rising sharp on all sides, and the kind of quiet you only get when you're actually bothered to climb for something. The walk up from Nant Peris takes roughly ninety minutes depending on fitness, and the path follows an old miners' trail - quite steep in places, but well-trodden enough.

This is for walkers and hikers who want altitude without the Snowdon circus. Families with young kids will find it tough going, though older ones who enjoy scrambling might manage it. If you're after lake views with minimal effort, head elsewhere - but if you want landscape that feels genuinely wild, this delivers.

Timing matters. Spring and early summer give the best conditions; winter can be grim. Allow half a day minimum if you're coming from Bangor, longer if you're pottering around Ogwen Bank Caravan Park nearby and want to make a proper outing of it. Admission is free - you're just walking across the hills.