runway 13r at palm springs international airport
at one end of a runway
according to the international civil aviation organization (icao), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". runways may be a man-made surface (often asphalt, concrete, or a mixture of both) or a natural surface (grass, dirt, gravel, ice, sand or salt). runways, as well as taxiways and ramps, are sometimes referred to as “tarmac,” though very few runways are built using tarmac. runway lengths are now commonly given in meters worldwide, except in north america where feet are commonly used.