Kryptos is a piece of art-work at the CIA Headquarters. It contains four encoded texts. The text on the fourth panel remains undeciphered.
The sculpture has been a source of mystery and challenge for CIA employees, other government employees, and interested people outside of government. In early 1998, a CIA physicist announced to the Agency that he had cracked the code for three of the four sections. This was followed a year later by a public announcement from a California computer scientist that he had done the same. As varied as the codes in the sculpture are, so were the methods to crack them. The Agency employee used pencil and paper, and the computer scientist used his computer. No one has yet to break the code for the remaining 97-character message which utilizes a more difficult cryptographic code.
Visit the Kryptos Page on the Village Interweb to find out more about this, and possibly be the first person to crack the code!