It all started with a drought season, like the one currently affecting part of Spain, including Catalonia. Desperate due to lack of water, farmers in the central Chinese province of Shaanxi began to excavate a field in search of an aquifer that would alleviate the pain of their crops.

When they had barely dug a trench a meter deep, they came across hard, red earth. They cleared away that unusual layer and their eyes couldn’t believe what they had found. Buried was a life-size clay head and several bronze arrowheads.

This is how, on February 2, 1974, exactly fifty years ago, one of the great archaeological treasures of all time was found by chance, the thousands of human sculptures from the terracotta army of Qin Shi Huang, the first emperor of China. , also known as the warriors of Xi’an.

The peasants of Shaanxi had found the tip of the iceberg and the archaeologists were in charge of opening the melon to the bottom. Subsequent excavations revealed that the crop field was located on a series of 56 square kilometer pits filled with thousands of figures of soldiers and war horses, as well as acrobats, officials and other animals.

The mission of this formidable terracotta troop was to protect the nearby mausoleum of Qin Shi Huang, the man who unified China in 221 BC. and he ruled with an iron fist until his death in 210 BC. But half a century after its discovery, the emperor’s tomb remains sealed.

Because? Well the answer is not simple. An important role in this story was played by a text written by the ancient historian Sima Qian almost a century after the death of Qin Shi Huang (legend says that it was due to ingesting a mixture of jade and mercury prescribed by his alchemists).

Sima Qian’s account says that the grave is connected to booby traps that were designed to kill any intruder. “Palaces and towers were built for a hundred officials, and the tomb was filled with rare artifacts and wonderful treasures. Craftsmen were ordered to make crossbows and arrows ready to shoot anyone who entered. Mercury was used to simulate the hundred rivers, the Yangtze and the Yellow River, and the great sea, and it was set to flow mechanically,” the text reads.

Researchers believe that, more than 2,000 years after the burial, the death traps could fail, but no one wants to risk a flood of toxic liquid mercury – then considered an ‘elixir of life’ – affecting archaeologists. .

A study published in the journal Scientific Reports in 2020 confirmed this. Experts from South China Normal University said mercury concentrations around the tomb were significantly higher than would be expected in this area.

“It is possible that, over time, highly volatile mercury is leaking through cracks that developed in the structure. Our research has made measurements from three different locations around the mound and supports ancient chronicle records from the tomb, which is believed to have never been opened or looted,” the authors stated.

The fear of destroying the remains once the mausoleum has been opened has also stopped specialists. Currently, only invasive techniques can be used to access the tomb, running a high risk of causing irreparable damage as already happened in the excavations of the city of Troy carried out by Heinrich Schliemann in 1870.