France, Haute Savoie, Chamonix-Mont-Blanc, Montenvers, The Mer de Glace, on which we can see the current cave, the 500 metal stairs that descend there and the Drus, (3754 m), origin (in 1946) we set foot directly on the glacier, Since then, more than 580 steps have been added, attesting to the spectacular melting of the glacier