a robber goes into a bank and demands some money.
They give him a shell, four goats, six tomatoes and eleven chickens.
Before the invention of coins and paper currency, people used such things for buying and selling.
This exchange of goods and services for other goods and services is called barter.
Around 9000 BC people paid for goods with animals like cows, sheep and camels.
Some societies used vegetables and plants,too.
Then in 1200 BC people in China started using shells as money - mainly the cowrie shell.
Soon other countries began to do the same.
The cowrie shell was very successful.
It was used longer and in more places than any other currency in history.
The next development was in 1000 BC, when China started making bronze and copper cowrie shells.
It wasn't long before the Chinese made round coins out ofmetal.
The very first coins often had holes in tham so that people could pass a piece of string through them to keep them together.
By 500 BC metal coins had begun to appear in countries like Persia and Greece, and later in the Roman Empire.
These were usually lumps of silver with heads of various gods and emperors stamped on them to shoe they were real.
A few hundred years later leather was used as money in China, and 806 AD the first paper banknotes were produced by the Chinese.
It was still many years before paper currency appeared in Europe.
There centuries passed before it was used in all European countries.