In July 2022, mountain guides Frederic Degoulet and Benjamin Ribeyre set out to attempt a mountaineering first – to complete a circumnavigation of the Mer de Glace, France’s largest glacier, via some of the most emblematic peaks in the Mont Blanc range. The obvious line on the map had not yet been completed, even though it contours one of the busiest mountain ranges in the world. After an abandoned attempt in 2021, the journey turned into a race against time and temperature for the pair, with record temperatures across the Alps.