Technically off-topic, but this article from The Wall Street Journal on the off-site storage used by New York museums to hold the portion of their collections (sometimes as high as 90%) that they cannot display.
The Guggenheim, for example, keeps its artwork near a former strip club in mid-town Manhattan. MoMA, oddly, keeps its artwork somewhere in Long Island City.
The foundation that operates the Guggenheim took out a $2 million mortgage against its Midtown property in 1989, according to public records. A capital project completed in 1992 and overseen by Thomas Krens, the foundation’s director until 2008, included “a new storage and technical services facility on New York’s West Side,” according to information available on the museum’s Web site.
Along with art storage the outpost now includes conservation, fabrications, preparation and photography departments, according to a person familiar with the matter.