BASE jumping is the recreational sport of jumping from fixed objects, using a parachute to descend safely to the ground. “BASE” is an acronym that stands for four categories of fixed objects from which one can jump: building, antenna, span, and earth (cliff). Participants exit from a fixed object such as a cliff, and after an optional freefall delay, deploy a parachute to slow their descent and land. A popular form of BASE jumping is wingsuit BASE jumping.
In contrast to other forms of parachuting, such as skydiving from airplanes, BASE jumps are performed from fixed objects which are generally much lower altitude, and BASE jumpers typically carry only one parachute. BASE jumping is significantly more hazardous than other forms of parachuting, and is widely considered to be one of the most dangerous extreme sports.