BASE jumping, also sometimes written as B.A.S.E. jumping, is parachuting or wingsuit flying from a fixed structure or cliff. “BASE” is an acronym that stands for four categories of fixed objects from which one can jump: building, antenna, span, and Earth (cliff).[1][2] Due to the lower altitudes of the jumps, BASE jumping is significantly more dangerous than skydiving from a plane. In the U.S., BASE jumping is currently regarded by many as a fringe extreme sport or stunt.[3] In some jurisdictions or locations, BASE jumping is prohibited or illegal; in some places, however, it is permitted. BASE jumping became known to the wider public by depictions of BASE jumping in a number of action movies.