It's fair to say you've never heard of Dean Potter, we're guessing. But what you're about to watch the extreme outdoorsman do will have your heart trying to find a way out of your body.

Potter is known for BASE jumping and a number of other mountain and elevation-related exploits -- the kind that are extremely risky, release comically insane amounts of adrenaline and make you all the more thankful for a desk chair in a building with four walls. After all, you wouldn't rather be highlining (the modern form of tightrope walking) over a 3,000 foot gorge in Yosemite, would you? Potter most certainly would.

That video is all kinds of "Nope." Potter takes two steps over the gorge, and our fingers are already out, testing the wind for the slightest shift in direction. No way, no how, would you ever find any of us even standing on the ledge looking over, let alone walking out. We applaud you if you were even able to watch the whole video without hitting pause.

Don't believe it's real? It's not the first time Potter has tempted fate. His exploits have been chronicled by many, including the New York Times.

Follow us on Facebook and Twitter to read them first!

Is it legal? And as far as we can tell, this is not forbidden in Yosemite National Park. The rules steer visitors away from defacing any natural elements of the beautiful park. But Potter has always insisted he never does that. If you're looking to us for an endorsement, we say: No. Not at all. Ever.

You can breathe again, by the way.

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