How does a crane go up and down? – Spencer, aged four, UK
When you see the metal arms of a crane – known properly as a tower crane – against the skyline, you know a new building is going up in your city or town.
Many of the materials and machines on a big building site are too heavy for people to lift by themselves without getting hurt. Using a tower crane means that building materials can be lifted easily and quickly, even when something very tall is being built, such as a skyscraper.
