Few stories have the power to captivate us more than those that remain unresolved. Codes, puzzles and cryptic public art tease us with their intrigue: Why is their message coded? What great secrets might they hide? Despite the efforts of our most revered historians, cleverest cryptographers and most determined treasure hunters, history is replete with riddles that continue to confound us today. Fictional tales like those featured in “The Da Vinci Code” and the movie “National Treasure” have got nothing on these real-life puzzles. Here's our list of 10 of the world's most cryptic unsolved mysteries and codes.