Air pressure at greater elevations is low, and here on the ground it’s high. (So at sea level, air pressure is higher than it is at Mount Everest.) We can’t feel the high air pressure here because it matches the pressure inside our bodies. We can see pressure demonstrated when we remove air pressure from the inside of a sealed bag: the contents get squeezed by the higher air pressure on the outside. And when an enthusiastic student — with a trained professional on hand — is vaccuum-packed, he can feel the air pressure, too! (Never put a bag on or over someone’s head, and do not vacuum-pack a person. The vacuum-pack demonstration that we use is very specifically tailored for safety issues and so Ellis was completely safe.)