Blue Fin Building

Allies & Morrison, The Blue Fin Building, London, 2007

Steel

Steel was developed in 1856. It is made from iron that has been mixed with carbon. Adding carbon makes steel hard, strong and brittle. Steel is very good at standing up to forces that try to bend it. It therefore makes an excellent building frame.

The great strength of steel allowed skyscrapers to be built.  Designers still do not know how tall the tallest possible steel framed building could be, but it is probably at least 1,600m (1 mile) high.

Today over half the steel that is made is recycled, making it a little more environmentally friendly.