It’s a 4300-year-old walled metropolis. At its heart is a giant step pyramid — lavishly adorned with stone stylised eyes and faces.

Now called Shimao, it’s ancient name is long since lost.

But its significance was — and is — enormous.

It was once a thriving Bronze Age trade hub. Covering some 400 hectares, it was also one of the largest cities in the ancient world.

It was also the centre for murderous ritual worship.

According to a study published in the journal Antiquity, the city thrived for some 500 years before falling into rubble.

Pyramid of the eyes

It’s not a pyramid in the traditional sense. Its sides are not straight or equal. And it was moulded out of a hill, given its shape with rammed-earth and given strength by stone retaining walls.

But it is an enormous stepped mound covering some 24 hectares at its base, and 70 metres high. In comparison, the Great Pyramid of Giza covers some 5.5ha, but reaches some 139m into the sky.

The Shimao structure’s stone buttresses form 11 steps. And these appear to have been heavily decorated. Part-animal, part-human faces have been found etched into its stones along with distinctive eye-like symbols.

These “may have endowed the stepped pyramid with special religious power and further strengthened the general visual impression on its large audience,” the researchers wrote.

The topmost ‘step’ of the pyramid was a large plaza, upon which structures were built.

Among the 4300-year-old city remains are a water cistern, pillars, tiles and fine-quality domestic items, such as pottery.

“(These were) extensive palaces built of rammed earth, with wooden pillars and roofing tiles, a gigantic water reservoir, and domestic remains related to daily life,” the study reads.

Archaeologists have also found a mural at the site, which they think could be among the oldest in China.

The pyramid was visible from every aspect of the city, providing a “onstant and overwhelming reminder to the Shimao population of the power of the ruling elites residing atop it”.

“At the entrance to the stepped pyramid were sophisticated bulwarks (walls) whose design suggests that they were intended to provide both defence and highly restricted access.”

But it was more than just a retreat for the elite.

Valuable craftsmen appear to have been protected by its walls.

“Evidence so far suggests that the stepped pyramid complex functioned not only as a residential space for ruling Shimao elites, but also as a space for artisanal or industrial craft production,” the study reads.

Human sacrifice

Apart from being a hub of regional trade, Shimao also appears to have been a religious centre.

Jade was ritually inserted between most of the blocks in Shimao’s walls. And the remains of what appear to be human sacrifices have been found in six pits at several locations around the outer ramparts of the city.

“The jade objects and human sacrifice may have imbued the very walls of Shimao with ritual and religious potency,” the study says.

“In the outer gateway of the eastern gate on the outer rampart alone, six pits containing decapitated human heads have been found. Morphological analysis of the human remains suggests that the victims may have been related to the residents of Zhukaigou (a nearby city), which could further suggest that they were taken to Shimao as captives during the expansion of the Shimao empire.”

And it was a city prepared to fight.

The entire suburban sprawl — not just the central pyramid — was protected by wall, ramparts and bastions.

“Analysis and comparison of new archaeological data … have revealed a highly complex society, the political and economic heartland, and possibly the most powerful (civilisation), of the territory of what is today China,” the Antiquity article reads.

“Not only (was Shimao) the largest walled settlement of its time in ancient China, but was also among the largest centres in the world.”