It's slow-motion parkour for insane people. Or more specifically, for people who are even more insane than those who do regular parkour. And they're almost definitely all some kind of mutant, since nature instilled in us a fear of heights for a damn good reason. If you're within arm's reach of a sturdy surface to hold onto, check out this video of some guys scaling the world's second-tallest building, all the way to its horrifying pinnacle:
Buildering is usually illegal, because even if suicide isn't a crime where you live, it's still generally frowned upon to ruin somebody's brand new Kia with your exploding skull. Still, it makes for some amazing photos:
The photographer then tried a selfie. He will be missed.