In the real world, swimming is a skill that usually must be learned over a period of time - and that's just for swimming on the surface. Swimming underwater is another skill all on its own that must be learned, and even then, no human can stay under for more than a couple of minutes or so at the most without the aid of some special equipment, or some continuous training to boost lung capacity. Compare Super Not-Drowning Skills. Contrast Super Drowning Skills and Hazardous Water. See also Water Is Air.