Alone on the WallAlex Honnold is one of the world's best 'free solo' climbers; he scales impossible rock faces without ropes, pitons or any support of any kind. Exhilarating, brilliant and dangerous, there is a purity to Alex's climbs that is easy to comprehend, but also impossible to fathom; in the last forty years, only a handful of climbers have pushed themselves as far, 'free soloing' to the absolute limit of human capabilities. Half of them are dead. From