7km long, 200m thick and covering 40 km², this is France's biggest and one of the biggest glaciers in continental Europe, accessible by the Montenvers rack railway (Chemin de fer du Montenvers), opened in 1909. The ride up takes about 20 min. From the Montenvers Station one has great views on the glacier but also on the north Face of the Grand Jorasses, one of the three most famous North faces in the European Alps. At the mountain station you can also visit an ice cave inside the glacier itself (accessible by a short cable car ride), a cave serving as a small crystal museum, a small glacier museum in a hut and a historical grand hotel part of which also functions as a museum. All these sights are free.