High above the Valais valley sits a lake most people assume was always there. Lac des Dix holds up to 400 million cubic metres of water — the largest artificial lake in Switzerland by volume — and it only exists because of the Grande Dixence Dam, a concrete colossus completed in 1961 that still ranks as the highest dam in Europe. Its main job is hydroelectric power, but the turquoise water and the trails around it have turned the reservoir into one of the Alps' more rewarding summer detours.
That striking colour comes from mineral-rich mountain runoff rather than anything added, and it shifts with the seasons and the light. The surrounding terrain supports deer, ibex and plenty of birdlife, all easiest to spot between late spring and early autumn, when alpine pastures, waterfalls and nearby glaciers come into play.
Getting there is straightforward if you time it right. Sion's airport is under an hour away by car, though commercial flights there are limited; Geneva is the practical gateway at just over two hours' drive. Crucially, the roads that make the dam and lakeshore accessible only open from June to October, so this is firmly a warm-weather trip. Winter visits are possible but genuinely difficult.
The classic experience is standing on the dam's crest. A winding path takes about 45 minutes to climb, or you can skip the sweat and take a cable car. Up top there are panoramas over the lake and the Alps, plus tours inside the dam itself — and, unexpectedly, a climbing wall and zip line with rental gear available on site.
Hikers have plenty of options beyond the dam. The family-friendly Lac des Dix Path circles part of the shoreline on gentle gradients, suitable for beginners and children, with glacier views and old tunnels along the way. For something more demanding, the Plafeuri Hut trail starts in the village of Hérémence and covers nearly six miles with over 2,400 feet of climbing. It's one of 23 routes in the region converging on the hut, a simple but well-loved overnight stop with sweeping views back over the lake and the dam.
For travellers who have ticked off Interlaken and Zermatt and want alpine scenery with fewer crowds, Lac des Dix is a strong pick: dramatic engineering, turquoise water, and trail networks that suit everyone from toddlers to backpackers. Just plan for summer — and if your trip falls outside June to October, redirect to one of Switzerland's more accessible alpine villages instead.
