The monster calf-muscles on Michael Griesmeier are no surprise, after conquering 20,002 stairs with a 66lb backpack, setting a new world record.  The twist? He's vegan.

In collaboration with the Albert Schweitzer Foundation for Our Contemporaries, vegan extreme athlete, Michael Griesmeier, has set the world record in stair running while carrying a 30 kg backpack: during the course of six hours, he carried the heavy weight up and down 20,002 stairs (original source):