Since the beginning of civilisation, artists have created work of beauty. And since that time these pieces of national culture have also vanished from the nations that created them. Sometimes, private individuals are responsible. Smuggling and trading in illegal art and treasure is big business and worth billions of dollars a year. The dealers buy stolen goods from a country and quickly ship them abroad. Then, to sell them, they must have historical documentS for the objects which say where they were made, who made them, when they were made and who owned them. If the artefact is stolen, then they have to create a fake history for it.
However, there are also many examples of rare objects which are on display in famous museums bur were also taken from their original country. Many people believe there is little or no difference between these museums and the criminals who trade in stolen works.