Action movie fans know that a lot of the things they see during a stunt-packed movie are done in front of a green screen with some clever visual trickery. A lot of things, but not all of them.

Say what you will about Tom Cruise, but the actor does not seem to be lacking in...let's just say "guts." He actually did climb around the outside of the Burj Khalifa (the world's tallest building) in Dubai. He and the director of Mission Impossible: Ghost Protocol, Brad Bird, decided the best way for it to look like Cruise's character, Ethan Hunt, was precariously hanging from the outside of the building was to...wait for it...have him actually hang around the outside of the building (for an interesting read on how they did it, click here).

The latest Mission Impossible movie, "Rogue Nation," is opening soon, and trailers for the film are playing everywhere. The clip that's drawing the most attention involves Tom Cruise hanging onto the outside of an airplane in the midst of take-off. I've gotta say, it looks very realistic.

There's a reason for that: