Concrete

Concrete may seem like a very modern building material, but it was actually invented by the Romans. They made it by mixing fragments of stone with a mixture of lime and sand. The sand they used was volcanic earth called ‘pozzuolana’, which comes from the Pozzuoli region of Italy.

The Romans used concrete in many spectacular buildings. Structures like the Colosseum (shown below), the great amphitheatre in Rome, would have been very difficult to build without concrete.

After the fall of Rome in AD 476, something happened that is very unusual in the history of inventions. The art of making concrete with pozzuolana was forgotten in the West.

It was rediscovered in 1576 by British engineer John Smeaton, who was looking for a material with which to build the foundations of the Eddystone Lighthouse in Devon. Later engineers discovered that other sands could be substituted for pozzuolana, and the use of concrete in building became widespread once more.