Hunched over a rock at 5650m the sun belated down on my lifeless body. The time was 8am, day two. We had been walking for six and a half hours. 150m from the top of El Misti, a volcano just out of Arequipa, Peru. For the past few hours I’d stumbled on, drunk on the lack of oxygen to my brain. Concentrating on each step that sucked the energy from every inch of my mind and body. An hour earlier I had looked up, all I could see was rocks that stretched on for eternity. I was assured that top was only an hour passed this rocky wall.