"Everything is limited by its capacity for survival. In this sense, protecting cultural relics is actually extending their lifespan. Under the current conditions, we can preserve Dunhuang for at least 1,000 years," said Fan Jinshi, president of Dunhuang Research Academy, recently.

Dunhuang, a series of grotto caves with spectacular murals is indeed a pearl amongst the splendors of the ancient Silk Road route and a treasure of the Chinese nation. It has a history of over 1,600 years.

Acoording to Fan, the Dunhuang Research Academy takes "comprehensive protection measures" of Dunhuang, in particular preventing pollution of the area. The protection covers not only the cultural relics themselves but also its natural environment. The Dunhuang Research Academy staff supervise the hydrological and geological conditions of this area, but also study the paintings and the condition of the materials on which they are painted.

For example, it has been found that Dunhuang boasts a very arid or dry climate. However, rainstorms in summer months bring water to the mountain, which creates a reaction to the salt minerals in the rocks. This dampness with the salt will eventually erode the murals in the Mogao Grottoes. Currently, the Dunhuang Research Academy is in cooperative study with experts from the United States and Japan on how to prevent the erosion with X diffraction (X-ray) and infrared technology and what to do about the dampness entering the grottos.

Dunhuang has an increasing number of tourists each year, Fan said. In 1979, Dunhuang received about 30,000 visitors, the figure rising to 200,000 in 2000, and 310,000 in 2002. This large number is surely to affect the murals over time. Of the 735 caves in Dunhuang, 492 were found to contain frescos -- the very large ones exceeding 200 square meters. The middle caves are only 30 to 40 square meters while the smallest one is only several square meters. As a middle cave receives thousands of visitors a day, the temperature and humidity will surely improve. However there is no data currently to show how many visitors a day affect the murals and how much that influence will be. Last Spring, the Dunhuang Research Academy set up special equipment in these caves to investigate and once a conclusion is drawn, tourists will have to make appointments before their traveling to see Dunhuang.