Liu Huilin, deputy director of the Dunhuang Research Institute, said the center will provide visitors with a "virtual grotto cruise" during which they will be able to watch video tapes and showpieces, learn about the grotto's history and gain basic knowledge about its protection.

"If tourists can gather the information they need before entering the grottoes, their stay inside will be shortened, and that will be beneficial for the grottoes' preservation," Liu said.

Currently, every tour group accompanied by an interpreter spends an average of five to 10 minutes inside the grottoes, given that the interpreter has to recount their detailed history, he said.

In peak season, visitors swarm inside, one after the other, provoking sudden increases in temperature, humidity, and carbon dioxide and dust contents which constitute a serious threat to the survival of the painted frescos and sculptures, he explains.

In 2002, a total of 310,000 visitors visited the site, mostly during the week-long May Day and National Day holidays.

According to the institute, the annual visitor volume could reach half a million in the next five to 10 years.

To minimize potential damage inflicted by visitors, the research institute has commissioned three companies in Beijing, Shanghai and Lanzhou, respectively, to design a layout for the new customer service center.

If everything goes smoothly, Liu said, the center will be operational before 2006.

In 1900, a Taoist priest, Wang Yuanlu, discovered a cave in the Mogao Grottoes in Dunhuang containing more than 50,000 sutras, documents and paintings from nearly 10 dynasties covering the period from the 4th to the 11th century.

The Mogao Grottoes were included on the United Nations Educational Scientific and Cultural Organization World Heritage List in 1987.

(Xinhua News Agency April 8, 2003)