In 1955, De Riso documented an alpine excursion along the long ridge of Castor (Castore), in the Monte Rosa massif, following a night spent at the Quintino Sella Hut. The camera captures the two hikers, along with a third companion, as they advance roped up on the glacier, adjusting ropes and ice axes, and moving cautiously along the snow-covered slopes. The images alternate between close-ups of the participants and wide views of the surrounding peaks, highlighting the contrast between the dark rocks and the dazzling snow. The ascent towards Punta Castore, at over four thousand meters, conveys the rarefied and solitary atmosphere of the high mountains, with glimpses that reveal the vastness of Monte Rosa and the spectacular nature of the alpine landscape.