First Motorcycle Double Backflip
The first rule of motorcycle riding for most people is "don't flip over." It's pretty hard to maintain control over your bike when you're upside down. Then again, that rule gets flipped on its head if you're a motorcycle stunt rider. If that's your job, you want to flip over as many times as you can.
The first double backflip on a motorcycle was completed by Travis Pastrana in the 2006 X Games, when he was competing in the Moto X Freestyle event. The double backflip was long considered a trick that no one would ever land, and as Pastrana told ESPN in 2014, there's a good reason for that. "The first thing you need to know about the double backflip is that is that there's just no way to bail out," Pastrana said. "If you bail out you're going down on your face with a motorcycle on top of you. You can't even take a second to spot your landing in between flips, because if you do you won't make it" [source: Bane].
It goes without saying that the double backflip is one trick you shouldn't try at home.