They came in their droves, all hoping to catch a glimpse of what is considered to be one of Mother Nature's more unusual spectacles.
However, these spectators unwittingly became part of the show when a huge tidal bore burst through a dam and spilled over the riverbank, sweeping scores of tourists off their feet.
One moment these bystanders stood transfixed at the banks of the Qiantang River in Haining, in east China's Zhejiang province, waiting to witness the natural phenomenon. See more photos below:
Tidal wave: Spectators scatter as the water crashes over them in one of Mother Nature's more unusual phenomena
Swept away: Police try valiantly to protect the crowds from the tidal surge, including women and children, but the sheer weight and speed of the water carries off everyone in its path
The next they were running for their lives as a huge wave came crashing towards them, engulfing the crowds while others looked on helplessly.
While there were no fatalities, more than 20 people were injured after the wave swept through the throng, and some had to be be carried to receive medical attention.
The astonishing natural phenomenon, which is an abrupt uprising of river water, happens when the moon's gravity influence tides from the sea, moving them upstream, resulting in the mesmerising bore.
Frenzy: The water engulfs the tourists, knocking some off their feet while others can only look on in horror
Wounded: The injured are carried away from the scene after the tidal bore crashed through a dam and swept through a crowd of spectators
Stretchered away: A woman is carried from the scene after the bore broke the banks of the river. More than 20 people were injured by the rogue wave, with many needing to be carried away for treatment
More than 20 people were injured by the rogue wave, with many needing to be carried away for treatment.
Despite the authorities warning onlookers to stand back from the river bank, many fail to heed the advice and end up trying to out-run the wave when it heads towards them.
Bores only occur in a few locations throughout the world, usually in areas with a large tidal range and where incoming tides are funnelled into a shallow, narrowing lake or river.
China's Qiantang River boasts the largest bore, up nine metres - or 30 feet high - and travelling up to 25mph.
Awesome power: Debris flies into the air after the water, which travels at speeds of up to 25mph, slams into the bank of the river. Many spectators are already beginning to panic
Swamped: The owners of this van may be having to hitch a ride home with someone else, after the river waters flow over the protective dam and engulf the vehicle
Standing her ground: A Chinese television news reporter, keen to get the best possible location for her piece to camera, is unaware of the huge wave behind her. Thankfully, she was not injured
The annual event is becoming a bit of a headache for authorities, who each year tell spectators to keep their distance from the tidal surge.
But, each year, daredevils and unsuspecting spectators stray too close to the river's edge, erroneously thinking they can outrun the wall of water.
In September 2008 a group of American surfers convinced the Chinese government to allow them to surf a section of the river.
Personal watercraft were used to safely transport the surfers in and out of the tidal bore.
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