castor and pollux summit on monterosa traverse knife edge snow ridge glacier walk and climb in the alps

adventure aerial alpine alps aosta beautiful blue breithorn breuilcervinia champoluc climb dangerous edge europe exposure glacier gressoney hamlet haute italian italy knife knifeedged landscape lyskamm massiv matterhorn monte monterosa mountain mountains nature night outdoor panorama peak ridge rocky rosa route scenery scenic sharp ski sky snow snowy switzerland tourism trail travel traverse valley view walk white winter zermatt