During World War II, carrier pigeon 40TW194 died in Surrey, England while carrying an important message. The bird's remains were discovered decades later in a chimney, with the little red capsule still attached to its leg. Inside the red capsule was a coded message, revealing that the message was being sent to "X02" and that the message had been a duplicate of one carried by another pigeon. It is now believed that the bird was heading to Bletchley Park, the secret location of Britain's code-breakers during WWII. Apparently the other message, being carried by bird 37DK76 also never made it to its destination.
What does the coded message say? Experts still aren't sure, but they're working on trying to decipher the code. For more information about this interesting story, read this New York Times article.