Modern Marvels

One of the most useful machines ever created, the crane is a simple but important combination of the pulley and the lever. Though cranes have been helping us build civilization from at least the time of the Egyptian pyramids, the modern steel-framed construction cranes are a relatively recent development. Put on your work boots as we ride through the history of cranes from ancient days to skyscraper construction sites, ocean-freighter docks, and the International Space Station.