Stair Masters: Tower Running a Painful High

"Think about the most painful thing you've ever done, then multiply by 10," says one devotee (yes, devotee) of tower running, in which hearty soles summit the world's tallest buildings. The Empire State Building, the Sears Tower and Taiwan's Taipei 101 are some of the majors of the sport, the Guardian reports, whose upward momentum is undeniable.

Exercise benefits are, ahem, high, one biomechanics expert says: “Athletes have always used stair climbs as part of their fitness training. … Rocky did it, too.” But watch out, she warns: "As you get more tired, there is an increased possibility of tripping. In that respect, the injury you're most likely to suffer is to your nose or teeth." (More fitness stories.)