Wobbie, don’t die,” Robin Behl, 28, recalls hearing, moments after he felt certain he was going to die. It was towards the close of the 72 hours that he had to complete his summit of one of the world’s highest mountains, Nepal’s Mount Manaslu, that he recalls blacking out. “I don’t remember anything. I could hear my heart pounding, and was begging my Sherpa to increase my oxygen flow. He refused, and I begged him again. I was suffocating, and remember thinking I was certainly going to die.”

The words of a nine-year-old girl continued to ring in his ears as he drifted in and out of consciousness. “Wobbie, don’t die,” the “love of his life”—his mentor’s daughter—had told him when she heard from her mother that Behl was set to participate in one of the toughest climbs in the world in September. Mount Manaslu takes adventure-seeking climbers to a height of 8,163 metres above sea level, an elevation that, Behl says, is referred to as the death zone. “Human beings are not designed to survive above 8,000 metres,” says Behl, “In every moment that you spend there, your [health] depreciates. This is also why this summit is referred to as the fourth toughest one in the world. There are steep vertical climbs involved; one wrong step could mean the end of you. In certain sections, you can’t see or hear anything around you, and you’re constantly in a state of fight or flight.”