One of the greatest action set-pieces in recent memory, Brad Bird's Mission: Impossible - Ghost Protocol sees Tom Cruise scaling the outside of the Burj Khalifa, the world's tallest building at a vertigo-inducing 2,722 feet. Of course, the actor decided to perform the entire sequence himself without the use of a stunt double, adding further realism to an already nail-biting scene.Although securely attached to the building with a safety harness, Cruise admits that he failed to anticipate the crosswinds that come with being up so high, which caused him to slam into the side of the building on numerous occasions. However, the combination of the actor's dedication and some stunning camerawork create a sequence that is nothing short of awe-inspiring, with Cruise's sprint down the outside of the building a particular highlight.