"It's clear that during the Liangzhu era, rice cultivation in China had largely matured, becoming the base of a regional civilization, which itself lies among the roots of the Chinese civilization as we know it today," says Zhou Yun, curator of the Shanghai exhibition.

After conducting DNA testing on the rice remains from the aforementioned granaries, archaeologists have come to the conclusion that they were not of one single species, and were most likely to have come from different rice-cultivating centers scattered across the Yangtze River Delta region, mostly on the alluvial plains that separated Liangzhu City from the bay area to its east.

The location of the plains also meant that the paddy fields were the first to be affected whenever there was a marine transgression, which is exactly what many believe started to happen toward the end of the Liangzhu civilization around 2300 BC.

"They were probably caused by celestial tides, which happened regularly, say at the beginning and the middle of each month. Every time, a mixture of fresh and salty water would come in and then retreat, flooding the crops that could not sustain the saline water," says Wang. "The record of those transgressions is today kept in the multiple thin layers of silt covering large areas of the plain."

But there was probably more to it than just that. Some Chinese researchers who have looked into samples of stalagmites from caves southwest of the Liangzhu City site believe that around the time of the civilization's demise, there was a period of extremely high precipitation.

"The massive monsoons probably led to such severe flooding of the Yangtze River and its tributaries, that even the sophisticated dams and canals could no longer withstand the mass of water," says Zhang Haiwei, one of the geologist-researchers.

In face of water, nothing is impregnable.

However, the Liangzhu story will never come to a complete end as long as "water still pervades this land", says Wang.

Among other things, he was thinking about the construction workers who, even before the archaeologists, acknowledged the brilliance of Liangzhu engineering, and about the long embankment which today still forms a lake with its nearby mountain, a lake upon which the locals rely for irrigation and fish farming.

"The Liangzhu people built these structures to last," he says.

Contact the writer at zhaoxu@chinadaily.com.cn