Like the snowfields of Kilimanjaro and the ice in the Diamond Couloir, the Lewis Glacier is shrinking at an alarming rate because of global warming.

CNN: The snows of Erukenya

The pair had set out on a popular summer hike known as Le Couloir des Bossons near Mont Blanc - the Europe Union's highest peak.

BBC: UK father and son found dead in Alps are named

The massif's two highest peaks, Nelion and Batian, rise to more than 17, 000 feet, with 1, 000-foot-vertical walls leading to their summits and the famous Diamond Couloir in between.

CNN: The snows of Erukenya