durability

I don’t know that much about mountain climbing and ‘no,’ I’m not planning on taking up that sport as a part of my cardiac rehab, but I am quite impressed with those who do climb mountains … especially mountains like Mount Everest! More than 3,000 climbers have made it to the top. But, several thousand have failed—more than 220 dying in the attempt. And the place they most often failed was the South Summit to Hillary Step. There, there’s a knife-edge ridge made of ice, snow, and fragmented shale—10,000 feet...