On the morning of December 1st, 1948, the dead body of a man was found on Somerton Beach, South Australia. No identification could be found on the man, except the phrase "Taman Shud" which means "finished" or "ended" in Persian, was discovered on a piece of paper in a secret pocket sewn into the man's trousers. The piece of paper had been removed from the last page of the Rubaiyat of Omar Khayyam, a book thematically concerned with living one's life to the fullest.
The copy that the piece of paper had been removed from was located and in the back of the book were faint pencil markings of five lines of capital letters with the second line struck out (pictured). The markings are believed to be a secret code that remains uncracked to this day.
For more information search "Taman Shud".