There's an interesting article at Wired about the crazy cost of moving a major work of art. The article claims that when the Mona Lisa was moved to its more prominent spot in the Louvre last year, it cost 3.2 million British pounds to move it. And it was only moved several meters!
Here's how it worked when they moved another of da Vinci's paintings, Lady With the Ermine, from Poland to San Francisco:
The painting was shipped by air -- accompanied by two armed couriers who sat in first-class seats on either side of the Lady, who had her own first-class seat. The painting had been crated in Poland in a heat-treated wooden box, then placed in a metal container. The box had a homing device to trace it if it were lost. Perish the thought. On arrival in San Francisco, the airport had further armed security attached to an unmarked van. The painting was transported to the museum, where it was unpacked and displayed in a climate-controlled glass casing. A boundary was marked off 3 feet from the painting, beyond which viewers were not to go, Sanchez says.
And in case you're wondering where the Mona Lisa has traveled:
The Mona Lisa has been a world traveler. After getting to the Louvre by a circuitous route, it was once borrowed by Napoleon, who put it on his bedroom wall. His exile to Elba island brought it back to the Louvre. The painting was stolen in 1911 and showed up in Florence, where it originated. Then it went back to the museum, followed by a Nazi sojourn and a GI rescue, and then back to the Louvre again. It went to the National Gallery of Art in Washington, D.C., in 1963 and traveled afterward to New York, Tokyo and Moscow. Now, however, it is a permanent darling of the Louvre.