At nearly four feet tall, emperor penguins waddle pretty awkwardly across the ice. But underwater, it’s another story. They release millions of microbubbles from under their feathers, creating a thin layer of air that reduces drag and lets them rocket through the water. When leopard seals are on the prowl, that burst of speed can mean life or death. On assignment for natgeo, our cofounder paulnicklen traveled to Antarctica to capture this phenomenon. On his first day out on the ice, a leopard seal mistook him for a penguin, launched seven feet out of the water, and slammed into his chest, knocking them both down. Realizing its mistake, the seal slipped back into the sea. Bruised, shaken, and unsure if he should continue, Paul, in his usual style, decided to go straight into the water. As he hovered motionless in the crystal-clear blue, emperor penguins started shooting past, trailing silver bubbles, right in front of Paul’s camera. To this day, ‘Propulsion’ remains one of his most u...