Mountain bikers on Mont de la Saxe above Courmayeur in Italy, looking across to the Dent Du Geant

tour du mont blanc italy alps italian alps mountain mountain range weather rocks slope steep geology ridge erosion man exercise male tour du mont blanc footpath long distance footpath outdoors sunlight fit fitness ascend mountain biking track mont de la saxe dent du geant glacier glacial retreat climate change global warming mountain bike cyclist off roaf cycling