On the side of Tianmen Mountain (Heaven’s Gate) in China is a steep flight of 999 steps. It’s also the world largest parkour course.

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Earlier this year, pro freesrunner Calen Chan had the opportunity to run the full course—and take  POV video.

The whole run spans the length of basically three football fields, and has an average incline of 45 degrees.

“Obviously this was difficult, and I physically couldn’t sprint down the entire path of deadly drops without slowing down, but I did my best!”

Plus, he was the only person to run the whole course with a GoPro in his mouth!

Here’s his final run:

“So fun!” he wrote. “I wish so bad that I was at 100% though, because I know  could’ve done so much better. My quads were so weak from competing on the speed course while extremely jet lagged the day before.”

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“But it’s all good because I luckily didn’t get injured and I did the best my body could do at the time. ☺ Can’t wait to go again!!! ❤”

Check out Chan’s Instagram for other tricks and videos.