In 246 BCE, the year Ying Zheng took the throne of the state of Qin at the age of 13, construction began on his mausoleum at the foot of Lishan mountain, 35 kilometres east of modern Xi'an in Shaanxi Province, China. He did not know then that he would unify six warring kingdoms, standardise the Chinese writing system and currency, build the first version of the Great Wall, and take the title Qin Shi Huang — First Emperor of China. He knew only that he would need a burial.
The mausoleum took 38 years to build. According to Sima Qian, the historian of the early Han dynasty who wrote about Qin Shi Huang in his Shiji (Records of the Grand Historian) approximately 100 years after the emperor's death in 210 BCE, the project employed 700,000 workers — a figure that probably includes the broader construction force across all Qin megaprojects, not solely the tomb. What is not disputed is the scale of what was built.
The burial mound at Lishan is 76 metres high today, down from an estimated 120 metres at the time of burial, reduced by 2,200 years of erosion. Its base measures approximately 350 by 345 metres — a mass of rammed earth covering an area larger than many medieval European cathedrals. It sits within a rectangular enclosure defined by inner and outer walls, the outer enclosure measuring 2,173 by 974 metres. The terracotta warriors — discovered in 1974 when farmers drilling a well struck a ceramic figure at 1.5 metres depth — are in three pits roughly 1.5 kilometres to the east of the mound itself. They were the guardians of the eastern approach.
The Description in the Shiji
Sima Qian wrote: "Craftsmen were ordered to make crossbows set to shoot any intruder. Mercury was used to simulate the hundred rivers, the Yellow River and the Yangtze River, and the seas, and was set to flow mechanically. Above were representations of all the heavenly bodies; below, the features of the earth. Fish-oil lamps were set to burn for a long time."
This passage was treated as literary embellishment for most of the 20th century. Then, in the 1980s, soil scientists began conducting geochemical surveys of the burial mound. Mercury concentrations directly above the mound were measured at levels 1,000 to 2,000 times higher than surrounding soils. The pattern was consistent with a sealed underground source: the mercury was not diffusing outward, as it would if it were in open soil, but was concentrated precisely above the burial chamber. Sima Qian's rivers of mercury were not metaphor.
What the Terracotta Army Tells Us About the Tomb
The army is extraordinary in detail. Pit 1, the largest, contains approximately 6,000 life-size terracotta soldiers arranged in a battle formation facing east. Pits 2 and 3 contain cavalry, war chariots, and officers, covering a combined area of roughly 20,000 square metres. Each figure was individually modelled: different facial structures, different ear shapes, different hairstyles for different ranks, different armour configurations for infantry, cavalry, and archers. They were originally painted — traces of pigment survive under protective conditions — in bright polychrome; the red and green and black uniforms were visible when the soldiers were first assembled.
The terracotta army does not represent all of the outer burial complex. Other pits contain bronze water birds (cranes, geese, swans) posed in lifelike attitudes, bronze horse stables, stone armour sets assembled from small stone plaques linked by bronze wire, acrobats, and officials. The outer complex is a model of the imperial administration in miniature, waiting. The mound itself is something else: the emperor's personal domain.
Why It Has Not Been Excavated
The decision by Chinese authorities not to excavate the burial mound is formal and explicit. The National Cultural Heritage Administration has stated repeatedly that the mausoleum will not be opened until preservation technology has advanced sufficiently to protect whatever is inside from degradation on exposure.
This is not timidity. It is the lesson of the 20th century in archaeology.
When Howard Carter opened Tutankhamun's tomb in 1922, the process of documentation and removal took a decade and destroyed a significant proportion of the organic materials (fabrics, wood, leather) that were exposed to air. That was a minor royal tomb by Egyptian standards, buried with limited resources. Qin Shi Huang's tomb almost certainly contains silk, wood, lacquerwork, and bronze in quantities that would dwarf anything found at Thebes — and those materials would degrade in hours if exposed to air without industrial preservation infrastructure that does not yet exist.
The Dunhuang caves in Gansu Province provided an earlier lesson. Between 1900 and 1910, the foreign explorers Aurel Stein and Paul Pelliot purchased or removed tens of thousands of manuscripts and art objects from a sealed library cave discovered by a Taoist monk. The items they left behind, inadequately stored, deteriorated faster than those in museum conditions. The damage was not from malice but from the gap between discovery and preservation capacity.
What Modern Science Can See Without Opening
Muon tomography — a technique borrowed from particle physics, in which cosmic-ray muons are detected after passing through solid material, revealing internal density contrasts — has been applied to large Egyptian pyramids and is being developed for the Lishan mound. A 2020 study from Tsinghua University suggested the presence of an intact central chamber, though the resolution of current instruments is insufficient to characterise its contents.
Ground-penetrating radar and electrical resistivity surveys have mapped the outer burial complex's walls and access shafts without excavation. The results confirm a multi-walled enclosure consistent with Sima Qian's description. The crossbow traps he describes — automatically triggered devices to kill intruders — are likely real, or were real at the time of sealing; bronze trigger mechanisms of precisely the right type have been found in the terracotta army pits.
The mound will not be opened in this generation. The decision to wait, made by archaeologists who understand what happens when organic material meets uncontrolled air, is the most consequential act of restraint in modern archaeology. It is also, arguably, correct.
