The Inverted Jenny (or Jenny Invert) is a United States postage stamp first issued on May 10 1918 in which the image of the Curtiss JN-4 airplane in the center of the design was accidentally printed upside-down; it is probably the most famous error in American philately. It is also one of the rarest, this version is the only known on that includes the plate number.
The last time It was sold at auction it fetched $4,000,000.
