The underground palace boasts a microcosm of the heavens and the earth. The historical records of the first century BC state " Work on his tomb began as soon as Emperor Qin gained power. The tomb contains palaces and pavilions filled with rare gems and other treasures, and is equipped with crossbows to shoot automatically any intruders! The ceiling was inlaid with pearls to simulate the sun, stars and the moon, the floors and walls are said to be lined with bronze to keep out water and mercury was pumped in to give the image of flowing rivers. The tomb was an imitation of the world. Lamps were filled with 'renyu' cream to ensure an eternal flame".

Investigations show that a 12,000 square meter area featured a high mercury content. The variations of traveling mercury was 70-1500 PPb, a level more than ten times that of surroundings. It was supposed by archeologists that this resulted from volatilization and infiltration of mercury pumped in the tomb, which ties in with the records. It reveals not only the development of geographical science in ancient China, but also very considerable creative ability.

Astronomical features were also discernible. It was recorded that "A golden toad symbolizes the sun and a jade hare the moon. " The earliest records of astronomical paintings could be traced back to the early Warring States Period (475-221 BC.). A similar was later found in various Western Han Tombs (206 BC. -24 AD. in Luoyang, Henan province.

What then are the actual dimensions of these tombs with such a rich content?

Archaeological tests show the underground palace was built at a depth of at least 20 meters. A critical point depends on the impermeability of the tomb. It is estimated that the inner tomb lies at a depth of 50 meters, within a rectangle stretching about 250 meters in each direction, while the ground water level is thought to have been much higher. An area of some 300,000 square meters was covered by ground water. Even today, it would prove difficult to prevent seepage into the tomb. The historical records recount "Line the walls with stones, bond the interior wall with melted copper, and coat the outer wall with lacquer."

About 750,000 square meters of stones were used to construct the tomb. Stones were first engraved with beautiful patterns and then painted with lacquer to combat moisture. Seams were filled with melted copper and tin to make them watertight.

Secondly, tomb robbers, who appeared as early as the Warring States Period, were a major concern of the designers. For example, as a precaution the tomb was equipped with automatic crossbows aimed to shoot at intruders. No survey reveals the security of the tomb has been breached. Several holes reaching to a certain depth of 10 meters appear to be the attempts of would-be grave robbers.