As if by fiendish design, the highest points on earth loom tantalizingly at the limits of mankind's physiological reach. Mountaineers and M.D.s agree that above 8,000 m (26,246 ft.), a physical curtain begins to fall. Higher than this, the air is so thin that ordinary people can live for only several hours -- if at all. Trapped in the so-called death zone, says one climber who is familiar with these altitudes, "you can't shout for help anymore. You lose your sense of logic. And you die in euphoria, overestimating your own strength."
Only 14 summits, all of them in the crescent...