Only the second Beale Cipher has been cracked. Strangely, the key was the Declaration of Independence, signed by none other than Thomas Jefferson, with whom Beale happened to share a name. The cracked cipher stated that the treasure was buried somewhere in Bedford County, Virginia, where people still search for it today.
Phaistos Disc
The Phaistos Disc sounds like it's straight out of an Indiana Jones movie. Italian archaeologist Luigi Pernier discovered the clay-fired disc in 1908, which was inscribed with mysterious symbols which may be an unknown form of hieroglyphics. The artifact dates back to the second millennium B.C.