 It concerned three alpine guides who were buried in a crevasse during an avalanche on 20 August 1820 near the Rocher Rouges, high up on Mont Blanc, during an expedition organised by .Forty years later the remains of two of them were discovered, re-exposed within fissures in the Bossons glacier.They were lower down from the point where they were lost; the corpse of the third guide was discovered the following year.