The Liangzhu Culture was the last Neolithic jade culture in China's Yangtze River Delta, and was called "China's Venice of the Stone Age."

The culture developed a monumental water culture, which included advanced engineering structures, hydraulics, and a complex system of navigable canals, dams, and water reservoirs that allowed for the year-round cultivation of large agricultural areas.

The culture peaked around 4000-5000 years ago, but then vanished from the Taihu Lake area, resulting in a slew of theories about why it died out, some of which are still being debated today.

Although many have speculated that catastrophic flooding was to blame for the sudden decline, no one knows for sure.

"A thin layer of clay was found on the preserved ruins, which points to a possible connection between the demise of the advanced civilization and floods of the Yangtze River or floods from the East China Sea," geologist Christoph Spötl from the University of Innsbruck in Austria explained.

"However, no clear conclusions on the cause were possible from the mud layer itself."

Now we have a better idea of the deluge that engulfed this magnificent location.

Spötl and an international team of researchers examined mineral formations (or speleothems) such as stalagmites from two underwater caves in the region, which carry chemical traces of long-ago climatic conditions, in a new study.

Their analysis of the stalagmite samples, led by first author Haiwei Zhang of China's Xi'an Jiaotong University, shows that the collapse of Liangzhu City occurred during a period of extremely high precipitation that lasted for decades over 4,300 years ago, most likely due to increased frequency of El Niño-Southern Oscillation conditions.

Heavy monsoon rains are likely to have caused such catastrophic flooding of the Yangtze and its branches that even the most complex dams and canals were unable to withstand the massive amounts of water, devastating Liangzhu City and causing residents to evacuate.

Massive rainfall in the entire middle-lower reaches of the Yangtze River Valley, combined with geochemical evidence of flood deposits above the Liangzhu culture layer, suggests that fluvial flooding and/or overbank marine flooding transported by the Yangtze River plume hampered human habitation and rice farming, according to the authors.

After that, humid conditions persisted for hundreds of years, during which time other ancient cultures rose to temporarily succeed the Liangzhu - at least until another megadrought caused the "final extinction" of Neolithic human societies in the region.

Around the same time, Chinese society was set to embark on a transformative new chapter with the establishment of the Xia dynasty in 2070 BCE, regarded to be China's first dynasty, led by Yu the Great.

The findings are reported in Science Advances.