The annual Qiantang River tidal bore, which is expected to be seen this year during the National Day holiday week, attracts tens of thousands of people from home and abroad. [Photo by Pan Jincao/China Daily]

As early as the 4th century BC, China's famous philosopher Chuang Tzu (Zhuang Zi) described the huge tide as follows: "The waters in the Qiantang River will roll on, raising waves as high as mountains and towers, creating a thunderous roar and gathering up a force that threatens to engulf the sun and the sky."

A famous poet Su Dongpo in Northern Song Dynasty (960-1127) wrote:

"What on Earth can hope to create a spectacular sight,

Like the tides on the eighteenth of August at night."

Tide watching on the Qiantang has been a popular activity for centuries, dating back to the Han Dynasty (206BC-AD220).

It had also become a well-established event on the social calendar for both ordinary people and the royal court by the time of the Southern Song Dynasty (1127-1279).