weapons, and skeletons of both humans and animals. But the actual grave of Emperor Qin, who conquered six warring states and unified China, has remained untouched for over two millennia.

"It is best to keep the ancient tomb untouched, because of the complex conditions inside," Duan Qinbao, a researcher with the Shaanxi Provincial Archaeology Institute, told the China Daily.

Half a century ago, Chinese farmers stumbled upon an enormous underground mausoleum full of life-size clay people, animals and military equipment. Archaeologists think that the tomb may be an ...