When priceless really means priceless
According to the Guinness Book of Records, the Mona Lisa is the most valuable object ever insured. When it was assessed for insurance purposes before its US tour in the 1960s it was valued at $100 million. Current estimates vary from $700 million to $1 billion.
Mexican financier David Martinez was reported to have paid a staggering $140m for a signature abstract piece by American artist Jackson Pollock, making it the world's most expensive painting.
The boom in the art market has created a billion dollar parallel industry in stolen art, often related to drug cartels and illicit arms deals. Many thieves are motivated by the fact that reasonably valuable art pieces are worth millions of dollars and weigh only a few kilograms, at most. Transportation is also trivial, assuming the thief is willing to inflict some damage to the painting by cutting it off the frame and rolling it up into a tube carrier. It has led the global policing organisation, Interpol, to launch its own database of stolen art.