Professional rock climber and subject of the new documentary “Free Solo”

“I’ve gone on glacier-climbing expeditions twice around the Ruth Gorge in Alaska. That’s pretty terrifying. You have no idea where crevasses might be. These glaciers are like hard ice which has deep cracks in it, that’s all covered by a layer of fresh snow. You punch through it like a crust. But you never know if you’ll punch all the way through into an abyss. So each step you’re like, “This could be my last one!” In both expeditions there,...