††††A crane is a large machine used for lifting and moving heavy loads. The arm of a crane is called a jib or boom.
Around 250 BC, Greek scientist Archimedes is said to have single-handedly moved a large ship using pulleys, but nobody knows how he did this. In about 10 BC, the Roman Vitruvius wrote a description of a crane in an architectural book. Hero of Alexandria also described a crane in his book on mechanics.
Today there are three main types of crane: the jib crane, the overhead travelling crane and the tower crane. Most cranes have the machinery mounted on a revolving turntable. This may be self-propelled or fitted on a track.
