This is the Skyladder Parkour Course at Tianman Mountain in China. It consists of 999 steps and has an average incline of 45 degrees. Calen Chan, a 19-year-old freerunner fromUtah, got to run all the way down. With a GoPro camera held in his mouth!
Oh yeah, the video might make you a little dizzy. -via Laughing Squid
(Image edit: Calen Chan)