Looters destroyed some of Iraq's priceless artefacts
The looting of the Iraqi National Museum in Baghdad has focused mass attention on the illegal - and very lucrative - trade in stolen art and antiquities.
Stolen from the museum were some of the most important ancient artefacts in the world, including the Uruk Vase - the world's oldest narrative work of art - and the world's oldest cast bronze work.
"These are objects that appear in every introduction to art history," Professor Zainab Bahrani, an art historian at Columbia University in New York, told the BBC World Service's Analysis programme.
"In both of these cases we have objects which are examples of the first of their kind that then become imitated or inspire works of art in the rest of the world, throughout the history of art.
"Every student at university sees the Uruk Vase at and introductory class."
The art world is still in a state of shock from the theft - but it is not a new phenomenon.
"The illegal trade is 3,000 to 4,000 years old, if not actually older," said Godfrey Barker, an art journalist.
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Mr Barker added that he estimated 98% of antiquities are stolen.
The problem is that many works of art are instantly recognisable, so cannot be sold on the open market.
Instead, they are sold on the underground market and disappear, sometimes seemingly forever.
Mr Barker characterised the buyers: "James Bond's Mr Big, in a cave near Bangkok, may very well be staring, as we speak, at Raphael's Portrait Of A Young Gentleman, stolen from Krakow in 1940 and the most important loss of World War Two."
To combat the trade, the UN Educational, Scientific and Cultural Organisation, Unesco, has announced a three-point plan to tackle the problem of looting in Iraq.
It included pronouncing a ban on importing cultural objects from Iraq, immediate putting an inventory of missing objects, and establishing a mission to Iraq for a number of experts to begin restoring the country's cultural heritage.
"This is becoming the second traffic - after drug traffic - in the world," said Unesco's Assistant Director General for Culture, Mounir Bouchenaki.
Cash-strapped local farmers are digging up "find sites" to acquire the objects, thereby removing the history of the object, because they know they will find a willing buyer.
That kind of trade is so difficult to police, that Anna Summers-Cox - an advisor to the British government on trade in illegal art - believes moral pressure must be applied to buyers.
"It's rather like fur coats - everybody used to have a fur coat in the old days, nowadays there are not so keen because they think about the animal.
"Now with antiquities people think of the find site that would have been behind that object."
Ms Summers-Cox added that she felt what was needed was a database of all works of art that have been stolen - dealers would then be able to check if the item they were interested in was legal.
Charles Hill, who found Edvard Munch's The Scream after it was stolen from a museum in Oslo, recommended going one step further and offering incentives to recover important items.
"As far as dealers are concerned, their reputations are their most important possession," Mr Hill said.
"An amnesty initially, and then I think some sort of covering of their expenses later on for those who bought things in good faith," would help secure items from dealers worried about having handled stolen goods, he added.