Update Wednesday, June 25, 2014: A representative from Sotheby's tells NPR that the instrument did not sell "at this time."
Wednesday, Sotheby's auction house plans to announce the sale of a rare viola made by Antonio Stradivari. The minimum bid is $45 million. If it sells, it will be the most expensive instrument of any kind in history.
Here's an old musician joke: How do you keep your violin from getting stolen? Put it in a viola case.