But when the caves caught the interest of the international art market in the early 1900s, many of the artifacts were removed or badly damaged. Acid rain has eroded what remains.

Now researchers from the University of Chicago are trying to undo the damage to the caves--virtually. By using the latest in digital photography and 3-D topography, they hope to create a computerized vision of how the caves looked centuries ago.

Collaborating with universities, museums and research institutions across China and the U.S., the researchers will attempt to bring back the temples' original splendor by scanning the caves and the plundered artwork and merging the images in virtual reality.

Project leader Katherine Tsiang Mino, associate director of the university's Center for the Art of East Asia, tracked down objects from the caves as part of her dissertation and located more than 100 pieces. Most now reside in private collections and museums, with the biggest and most important in the United States.

"When I was studying, I found more and more of them, which was very exciting, but then it was also very sad to see how badly damaged the caves are," Mino said.

"I always thought it would be interesting to try and match up where the sculptures [in museums] had come from, and also bring some attention to these very important sites so that they can get the sort of resources they need to protect them in the future."

Because very little information exists about the short-lived Northern Qi dynasty, which lasted from year 550 to 577, the team also is hoping the reconstruction will give insight into the religious beliefs of the time and how imperial sponsorship influenced the design of the Buddhist sculptures.

In addition, the researchers hope to use the finished product--a three-dimensional virtual replica of the decorated caves--as a teaching resource at schools and museums. Their ultimate goal is an exhibit that would include some of the actual sculptures, allowing viewers to see the objects in person and in the context of the original cave setting.

The caves are believed to have been established by two Northern Qi emperors who were devotees of the Buddhist religion.

Looting of the caves began shortly after the Chinese revolution of 1911. A few years later, officials in charge of the ancient sites decided to repair them to attract tourism.

Repairs to the caves done in the 1920s and 1930s replaced missing heads and hands with new ones, but with no model to guide the effort, the replacements looked "rather funny-looking," Mino said.

On recent trips to China, Mino said she overheard discussions about future renovations to the cave sites.

"It made me worry and even shudder...what they could do if they did not have the right models or they really did not know what they were doing," Mino said. "The question would be, how close would it be to how the original statues were?"

The researchers hope the project acts as a prototype for future endeavors involving stolen or displaced cultural objects.

Many museums are being pressed to return ancient artifacts to their original homes. Greek officials are pushing for the return of sculptures from the Parthenon, known as the Elgin Marbles, for example. The new technology could allow museums to continue research on such pieces without physically possessing them.

In 2000, the Altamira Museum and Investigation Center in Spain completed a similar digital reconstruction of the Altamira Caves, considered the Sistine Chapel of prehistoric cave art.

The China project, funded by a Getty Foundation Collaborative Research Grant and the Carpenter Foundation, is the most ambitious to date, Mino said.

That's because in addition to digitally reconstructing the caves, the project will repopulate the caves with original artifacts.

"We knew we could do digital photography quite easily... but we wanted to do something a little more groundbreaking," said Lec Maj, technical coordinator of the project and computer research adviser for the division of humanities at the University of Chicago.

To replicate all the intricate detail found in the caves, objects are sectioned. Each section is labeled and scanned with a digitizer. Then the individual sections are fitted together in precise alignment, called registering, to create an exact three-dimensional model.

Color is added later through high-resolution digital photographs that are merged with the 3-D image.

"There are many different applications for this new technology," Maj said. "This is sort of groundbreaking in terms of archeology and preservation."