BASE jumping is essentially parachuting. The BASE part is actually an acronym for Building, Antenna, Span and Earth, meaning cliff. These are the fixed structures from which individuals hurl themselves. Exciting as it sounds, speeding through the air with the wind running through the hair, it is lethal. Apart from the obvious risk of jumping from hundreds of feet above, there s a chance of being thrashed by the wind. It is illegal in many countries, including in the US, except at organized events.