Rodents of Unusual Size
Fun until the gaping maw of the beast and it's many tentacles start to pull you down on your way up.

Cube
Fun until the ad agency style editing and annoying music makes you stop watching.

HankFinch
How did they waterproof the live techno band that was playing in real time?

Longshot-
You and me both. I was as scared as a little girl around spiders while snorkeling off of Guam.

I just dunno what's in those large dark underwater caverns.

Johnny Madhouse
I suppose it's conceivable that the cameraman let him borrow their oxygen (if they had any) every so often, but I know that this a legitimate sport. I now this because Scientific American Frontiers freaked me right the hell out with an episode about it when I was little.

It was a really dramatic way to learn about the dive reflex and training lung capacity.

This is some really beautiful photography. What a cool/freaky video.

Wander
The youtube description says it was all one breath, if you feel like believing a youtube description.

Rape Van Winkle
It was invisible oxygen tanks.

YakooMarkTwo
"shot on one breath" by one woman who magically has 5 cameras surrounding him simultaneously and no air bubbles from her breathing apparatus are in any of the shots. Aalso, she manages to get BELOW him before he jumps. Major shenanigans.

RockBolt
This could easily be done in one breath by these crazy free diving types, but for the purposes of filming this is clearly several different complete takes to shoot from each angle

TeenerTot
I saw a show about marine archeology or paleontology down in a blue hole cave. The diver scientists had to descend through a layer of some kind of acid at one point. Scary stuff.

RockBolt
No, free divers don't suffer from any decompression issues because they do not breathe compressed air at depth. When you scuba you can't surface quickly because the compressed air you breathed will expand and rupture a lung or bubble in your joints, since its pressure is higher than the ambient pressure of air at the surface. Free divers only have air breathed at ambient surface pressure in their systems, which compresses then expands only to its original volume

Aelric
You know, as soon as you said that I realized that I knew that. It's been over a year, I think I gotta get back in the water and remember all this stuff. My bad.