The Mer de Glace is France’s largest glacier: nearly 7 km long, curling beneath the Drus and the Grandes Jorasses. You reach it from Chamonix on a little red rack railway that has climbed to the Montenvers since 1908. At the end, a dramatic balcony over the ice and the peaks.
The visit
From the Montenvers viewpoint (1,913 m), the view drops onto the glacier. To reach the ice cave, carved fresh into the glacier’s flank every year, you take a gondola down, then a flight of steps. Inside, galleries cut into the blue ice.
Also on site: the Glaciorium, a small interpretation centre on how glaciers form and live, and the historic Montenvers hotel.
The glacier is retreating, and you can see it
The number of steps down to the cave grows year after year. It’s the clearest measure of the glacier’s retreat. Signs along the descent mark the ice level in past decades. The visit is beautiful. It’s also a reckoning.
Book a guided visit
With a guide, the Mer de Glace becomes readable: how it forms, the crevasses, the séracs, the history of mountaineering and of glacial retreat. Several outings combine the Montenvers with the Aiguille du Midi over a day. Here’s our selection from our partner.
Good to know
Allow time for the round trip to the cave. Between the gondola, the steps and time on site, plan about 1.5 to 2 hours from the Montenvers.
Good shoes. There are many steps, sometimes wet. Not the place for flip-flops or city shoes.
Book in summer. The train is mobbed in July and August; a dated ticket saves you the queue.
An easy family outing. The train does most of the climb; only the descent to the cave takes some energy. Kids love the galleries.
See also in Chamonix
Combine it with the ride up the Aiguille du Midi, or head out on the trails with a guided hike. Back to the destination: Chamonix-Mont-Blanc.