ice that glinted when the sun broke through the thick clouds. The view to the right, with a 1,000-foot drop, wasn’t much better. Here the dark, almost perpendicular walls were covered with rocks that protruded like knife blades. Alexander von Humboldt and his three companions moved in single file, slowly inching forward. Without proper equipment or appropriate clothes, this was a dangerous climb. The icy wind had numbed their hands and feet, melted snow had soaked their thin shoes and ice crystals clung to their hair and beards. At 17,000 feet above sea level, they struggled to breathe
