This is a story from autobiography of Nicola Tesla:

"On one occasion, when about 14 years old, I wanted to scare some friends who

were bathing with me. My plan was to dive under a long floating structure and slip out quietly at

the other end. Swimming and diving came to me as naturally as to a duck and I was confident that

I could perform the feat. Accordingly I plunged into the water and, when out of view, turned

around and proceeded rapidly towards the opposite side. Thinking that I was safely beyond the

structure, I rose to the surface but to my dismay struck a beam. Of course, I quickly dived and

forged ahead with rapid strokes until my breath was beginning to give out. Rising for the second

time, my head came again in contact with a beam. Now I was becoming desperate. However,

summoning all my energy, I made a third frantic attempt but the result was the same. The torture

of supprest breathing was getting unendurable, my brain was reeling and I felt myself sinking. At

that moment, when my situation seemed absolutely hopeless, I experienced one of those flashes of

light and the structure above me appeared before my vision. I either discerned or guest that there

was a little space between the surface of the water and the boards resting on the beams and, with

consciousness nearly gone, I floated up, prest my mouth close to the planks and managed to inhale

a little air, unfortunately mingled with a spray of water which nearly choked me. Several times I

repeated this procedure as in a dream until my heart, which was racing at a terrible rate, quieted

down and I gained composure. After that I made a number of unsuccessful dives, having

completely lost the sense of direction, but finally succeeded in getting out of the trap when my

friends had already given me up and were fishing for my body."