Yesterday, William Trubridge did something we might think is insane and many thought impossible - a dive of 100 meters on a single breath and without assistance at Dean's Blue Hole in the Bahamas.

That's right, he held his breath and went straight down - no fins, no weights, no airbag back up and a depth of three times what is considered safe.

Madness.   You can't even see the surface at that depth so you are running out of air but you have to know how to get there fast and without creating embolisms in the blood due to rapid decompression.

Total time on a single breath and in constant motion - 4 minutes, 10 seconds.  That in itself is an achievement but the physiological issues that occur at that depth - and while losing oxygen - make this a truly superhuman feat.