ST. LOUIS (AP) -- A few years ago, amateur photographer Robert Crowe discovered a bizarre and mysterious message embedded in the asphalt of a downtown street.
The colorful piece of mosaic-like artwork, about the size of a license plate, carried the seemingly indecipherable phrases: TOYNBEE IDEA IN Kubrick's 2001 RESURRECT DEAD ON PLANET JUPITER.
Puzzled, Crowe went to the Internet and learned that the so-called "Toynbee tiles" are an international phenomenon with similar pieces having been found on the streets of more than two dozen cities in North and South America in recent decades. Crowe eventually found three other tiles in St. Louis.
"One of the things that make cities enjoyable places to live is the unique details, quirks and oddities that make a place special," said Crowe, a lawyer by trade. "Toynbee tiles do that."
Crowe considered the tiles his special secret, but one he was happy to share, especially with out-of-town visitors. "They are more than extraordinary graffiti. They are tiny poems about science and philosophy."
They also are in danger.
In recent weeks, two of the four known tiles in St. Louis -- both on the south side of the intersection of Seventh and Market streets -- disappeared beneath a new layer of asphalt.
Todd Waelterman, the city's streets director, said the repairs were aimed at sprucing up the city in advance the Major League Baseball All-Star game at nearby Busch Stadium. He didn't realize the tiles had been covered and said he only had a vague recollection of their existence.
"They didn't show up in the records as being there," Waelterman said. "So we had no idea."
Even had he known, it probably wouldn't have made a difference. The city has made no provision to avoid the tiles' destruction, Waelterman said.
"These things are pretty willy-nilly out there," he said. "There's no easy way to get around it."
No one is certain who is behind the artwork or exactly how it is done.
The mystery has spawned numerous Web sites that document sightings and offer various theories about the tiles' origin and meaning. The general consensus is that the tiles first appeared in Philadelphia in the early 1980s, said Justin Duerr, a Philadelphia resident and self-described Toynbee tile fanatic. Other cities where the works have appeared include New York, Boston, Washington, Baltimore, Cleveland, Indianapolis and Kansas City as well as Rio de Janeiro, Brazil; Buenos Aires, Argentina; and Santiago, Chile.
Each mentions some variation of a message that typically references English historian Arnold J. Toynbee, who studied the rise and fall of civilizations; filmmaker Stanley Kubrick's movie, "2001: A Space Odyssey;" and resurrecting the dead on the planet Jupiter. Many include rambling and cryptic political messages. Others offer clues about how the tiles are made and encourage others to do the same. Some are done in red, white and blue color schemes, while others employ bright colors, such as yellows and greens.
Duerr believes the tiles are a mix of asphalt crack filler, glue and linoleum that are placed on the street and then covered with tar paper. Heat and pressure from vehicle tires meld the tile into the asphalt. As the paper wears away, the message is revealed.
About 130 of the several hundred tiles found worldwide, including those in St. Louis, are believed to be the work of the original artist, said Duerr, who visited many of the sites as part of a documentary he is involved with that he says will identify the artist. Don't bother asking him to reveal the mystery. He would rather you wait for the movie.
Some of the newest works, including several in Indianapolis, are believed to be the work of a copycat.
The St. Louis tiles aren't the first lost to new pavement or wear. Duerr said at least they were documented. Many weren't. "Those are the ones I really mourn."
Crowe, 59, lives in Webster Groves and has worked downtown for more than 30 years. He laments the loss of a beautiful, fascinating art form that has captivated so many people. The city, he says, is just a little more bland without them. "A small but unique and delightful detail about our city is gone."
(Copyright 2009 by The Associated Press. All Rights Reserved.)