The "Inverted Jenny" is a famous postage stamp issued by the United States in 1918. It features an image of a Curtiss JN-4 airplane printed upside down, which was a printing error. Only 100 of these misprinted stamps were produced, making them highly sought after by collectors. Due to its rarity and unique design, the Inverted Jenny has become one of the most valuable stamps in the world. In recent years, individual stamps have sold for hundreds of thousands of dollars at auctions, highlighting its significance in the world of philately and stamp collecting.