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A crane is a kind of machine, normally equipped with a hoist, wire ropes or chains, and sheaves, that could be used both to lift and lower products and to move them flat. It is generally used for raising heavy things and transferring them to various other areas. It uses several easy machines to produce mechanical benefit and thus relocate lots beyond the normal capability of a human. Cranes are commonly employed in the transportation industry for the loading and discharging of products, in the construction market for the movement of products and in the manufacturing market for the putting together of heavy tools.
The first construction cranes were invented by the Ancient Greeks and were powered by guys or draft animals, such as donkeys. These cranes were used for the building of tall structures. Larger cranes were later established, using the use of human treadwheels, allowing the lifting of much heavier weights. In the High Middle Ages, harbour cranes were introduced to load and discharge ships and assist with their construction-- some were constructed into stone towers for additional toughness and stability. The earliest cranes were built from wood,steel took control of with the coming of the Industrial Revolution.