See Erik Weihenmayer, the only blind person to summit Mt. Everest, as he crosses his first set of ladders over a crevasse in the Khumbu Icefall. The Icefall consists of a maze of hanging seracs and a jumble of living ice which flows continually downward, often dislodging blocks of ice the size of school buses. Many of the crevasses are hundreds of feet deep -- falling is a very bad thing. As Weihenmayer says, “The Icefall did not meet Americans With Disability Act standards.“