Unsolved mysteries have attracted curious people for centuries. One of the most famous examples of a mystery that has been baffling the minds of enthusiastic cryptologists for decades can be found on a statue that lies in the middle of the CIA headquarters in Langley, Virginia.The statue is the work of Jim Sanborn, an American artist who was commissioned to create the sculpture in the 1980s. It was unveiled in November 1990, and was titled Kryptos, hinting at the cryptographic challenge it presents to its audience. According to CNN, Sanborn knew that some of the world's greatest intelligence officers of the time would be passing by his piece every day, so he decided to create a work of art that would challenge them. Sanborn assumed that his coded puzzle would be cracked within a few weeks at most. It wasn't."I didn't think it would go on this long -- thirty years -- without being deciphered," Sanborn told CNN. Today, Kryptos is considered one of the world's most famous unsolved mysteries. Measuring six meters tall and six meters wide, Kryptos is a curved, screen-like statue made of copper and resembling the shape of a half-opened scroll. Its entire surface is full of cut out letters, nearly 2,000 of them in fact, which Sanborn says he "cut with jigsaws, by hand." Sanborn claims that Kryptos contains four encoded messages that when put together, form a riddle. But only three of the hidden messages have been deciphered over the years. The first message reads: "Between subtle shading and the absence of light lies the nuance of iqlusion." Sanborn intentionally misspelled the word "illusion" in an attempt to throw people off, which he seems to have accomplished rather successfully. The second message contains latitude and longitude coordinates for the CIA headquarters, while hinting that something is buried there. The message also mentions the initials "WW," most likely referring to William Webster, head of the CIA in 1990, the same year Kryptos was installed. The third message refers to writings by British archeologist Howard Carter, who in 1922 entered the tomb of King Tut.The fourth message still needs to be decoded before the riddle makes sense, and while many contact Sandborn claiming to have solved it, some of them for years now, he says no one has yet. "Our Kryptos community is made up of people all around the world. We have thousands of people that are interested in Kryptos -- either cracking it, or helping to see it cracked," according to Elonka Dunin, a cryptologist and video game developer who's been trying to solve Kryptos since the year 2000. When she realized that she couldn't do it alone, Dunin created a website dedicated to the cause, which has grown into a global network of people who all have one common goal - solving this mystery once and for all. Over the years, Sanborn tried to help the process by publicly sharing some clues regarding the elusive fourth message, in the form of three one-word hints: "clock," "Berlin," and, most recently, "northeast." But the mystery remains unsolved."I wouldn't be distraught if it ended tomorrow," Sanborn muses. "I'd maybe be relieved."