A rare 1918 US postage stamp featuring an upside-down plane that was stolen six decades ago and ended up in Northern Ireland was returned to its American owner on Thursday. Keelin O'Neill, who inherited the stamp several years ago from his grandfather, turned it over at the World Stamp Show in New York to the American Philatelic Research Library and collected a $50,000 reward in the process. But the mystery surrounding the Inverted Jenny remains: Who stole it and three other such stamps at a 1955 convention in Virginia? Two of the other stamps were recovered years ago, and the fourth remains missing. "I had no idea about the history and importance of the stamp until very recently," says O'Neill. "I have to say, it's quite fascinating, and I'm excited to learn more."
A hundred Inverted Jenny stamps were printed in 1918, until someone noticed the error. The misprint comes from a design that marked the launch of US airmail, featuring a Curtiss JN-4H biplane, nicknamed the Jenny. A wealthy collector, Ethel B. Stewart McCoy, bought a four-stamp block in 1936 and allowed the American Philatelic Society to exhibit them at the 1955 collectors' convention in Norfolk, Va. The stamps disappeared from a display case there, and it's been a whodunit ever since. Two were recovered in 1977 and 1982 from Chicago connoisseurs who had bought them. "I know this case is far from over, and I know our friends in the philatelic world will work very hard to see if they can solve the rest of the mystery," says the American Philatelic Society's executive director. (Read more stamps stories.)