Free diving is when you hold your breath while diving.
The world record in free diving is around 800 feet. Imagine diving that deep with just holding your breath, it’s insane.
There are many techniques how to do this right, some say you can slow down your own heart beat just by breathing slowly, some say the Yoga is the key, in any case everyone agrees you need to have great physical and mental strength to do this and survive.
This guy makes it look easy, he dances around like its piece of cake. Keep in mind, he needed to plan it all out, to carefully plan where to get in, where to get out, and to calculate exactly how much time it will take him.