Hundreds of people are now attempting to climb Mt. Everest every year. National Geographic's Mark Jenkins says the mountain, once tackled only by professional climbers, has become accessible to anyone who can afford to pay to go up and down.  And as a result, the mountain is being ruined by garbage, human excrement, and even bodies of deceased climbers. Also in this show, we learn about a new kind of aircraft, the “Aeroscraft."  It’s a space-age looking machine that’s almost as big as a football field and able to carry 50 tons or more.