Freediving requires both extreme courage and a profound zen-like calm. Without any breathing aids, freedivers fill their lungs with air and dive as deep as possible, swimming back up to the surface before their next breath. Lack of oxygen and intense water pressure at depth trigger physiological changes in their bodies, still not fully understood by science today, that prolong their survival underwater. These champion freediving athletes, who have dived to 125 m and more, are pushing the boundaries of their own physical capabilities – and those of the human race.