How do you break the unbreakable?
An art installation known as Kryptos was inaugurated at CIA headquarters in late 1990. The main attraction was a curved copper screen inscribed with a secret message. Three-quarters of the code have since been broken, but the final segment has resisted all attempts at decipherment. This video chronicles the cracking of the first three segments and examines the many clues that may one day lead someone to decipher the fourth.
