The exhausted climber scanned the frozen slope above him as darkness began to engulf the mountain. “Lino! Achille! Where are you?” he cried. The only answer was silence. It was July 30, 1954. At the end of a marathon day of load-hauling, Walter Bonatti and his gritty companion, the Hunza porter Amir Mahdi, had reached an altitude of 26,575 feet on Pakistan’s K2, the world’s second highest mountain.

At that moment, the K2 summit—arguably the greatest mountaineering prize of the day—lay tantalizingly close to the grasp of a large Italian team. Just four years before, with the French first ascent of Nepal’s Annapurna in 1950, what would come to be called the golden age of Himalayan mountaineering had been launched. By the mid 1960s, all 14 of the world’s peaks that surpass the benchmark altitude of 8,000 meters (26,240 feet) would be climbed for the first time.