Top 10 Most Expensive Auction Items

Auction house Sotheby's announced Sept. 9 that it will sell a rare John James Audubon tome, Birds of America, and expect it to fetch between $6.2 million and $9.2 million — making it the world's most expensive book. Only 119 copies of the bird book — most of which exist in museums and libraries — remain. Here's a look at some other pricey auction items

Going Once, Going Twice ...

Most Expensive Diamond

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Item: Wittelsbach diamond
Winning Bid: $23.4 million
Sold: 2008

If diamonds are a girl's best friend, the Wittelsbach would make one heck of a BFF. The 35.56-carat blue diamond dates back to the 17th century, when King Philip IV of Spain selected the jewel to be part of his daughter's dowry. The diamond passed among Austrian and Bavarian royalty for centuries, but after World War I Bavaria became a republic and the jewel was repossessed by the state. Christie's auction house tried to sell it in 1931 but apparently found no buyers. The diamond disappeared for a few decades only to resurface in 1962. A private collector purchased it in 1964, but sold it in 2008 for $23.4 million.

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