Extreme Sports
Snowboarder Marco Siffredi wanted to prove he could snowboard down Mount Everest, and he actually succeeded in doing it. But when he did, he was forced to descend down the Norton Couloir, because the Hornbein Couloir route didn’t have enough snow.
So he wanted to go at it again, this time in the fall – in order to have more snow. Although he made it to the top, he was already feeling exhausted, and probably suffered from lack of oxygen. He began to descend down the Hornbein Couloir route, but no one has seen him since.