In October 2000, terracotta civil officials were unearthed, and a year later a pit was discovered filled with life-sized bronze geese, swans and cranes. Some of the birds have arrived in London together with the terracotta acrobats.

More parts of the mausoleum have yet to be excavated and the real face of the underground palace below is still unknown.

However, modern technology does enable people to probe further into the mysterious mausoleum, and the location and inner structure of the underground palace have been detected.

According to archeological discoveries, the four-layered mausoleum includes an underground palace, an inner city, an outer city and open grounds, covering 56.25 square km, the size of nearly 7,900 standard-sized soccer fields. It is believed to be the largest underground imperial mausoleum in the world.

To dig or not to dig?

According to historical documents, construction of Emperor Qinshihuang's mausoleum began soon after his enthronement as king of the Qin state at the age of 13. Work was only completed two years after his death at age 50, with over 720,000 labors employed on the project.

For years, heated debates have crossed the country on whether the mausoleum should be further excavated. The prevailing opinion, including that of the government, is that it should remain untouched for at least the next 30 to 50 years.

It is not only a problem of money or technology, but out of consideration of cultural relics' protection, archeologists explain. The best protection for the mausoleums of ancient monarchs is not to excavate them, said Curator Wu, who has worked in the Qinshihuang Terracotta Warriors and Horses Museum for nearly 40 years.

"The relics lying underground for over 2,000 years have become acclimatized to their conditions after oxidation and decay in the early years of burial. If they are unearthed rashly, the temperature, humidity, wind, sunlight and other elements will cause damage," he warned.

"Silk clothes are the relics most difficult to protect," said Zhao Huacheng, a professor at the Archeological School of Peking University. "Frescos, lacquered wares and bronze works are better, but still easy to rust."

Zhao noted that China has already encountered problems in preserving archeological findings. "For example, the painted coffins and silk paintings excavated in an ancient tomb from the Han Dynasty (202 B.C.-A.D.220) have not been preserved very well," he revealed. In a certain sense, excavation means destruction, the professor said.

With this in mind, Chinese archeologists agree that they need to wait patiently even if some of them may not personally witness the true face of the underground palace of Emperor Qinshihuang. Aside from natural intervention or any new discovery by chance, it may take generations for China and the world to discover the further magnificence of what lies buried deep beneath the Shaanxi earth.