钱塘观潮（附图20张）

For hundreds of years, on the eighth month of the lunar calendar, people have gathered along the shores of China’s Qiantang River at the head of Hangzhou Bay to witness the waves of its famous bore tide. Higher-than-normal high tides push into the harbor, funneling into the river, causing a broad wave that can reach up to 30 feet high. If the waves surge over the banks, spectators can be swept up, pushed along walkways or down embankments. Below, I’ve gathered images from the past few years of the Qiantang bore tides.

A crowd of Chinese tourists run away as a tidal bore breaks over a barrier along the Qiantang River in Haining, east China's Zhejiang province, on August 31, 2011.

A remote controlled helicopter hovers over the Qiantang River as tourists gather on the river bank to see the soaring tide in Haining, on September 13, 2011. 

People run away from waves caused by a tidal bore which surged past a barrier on the banks of Qiantang River, in Haining on October 8, 2014.

Visitors run from waves caused by a tidal bore in Hangzhou, Zhejiang province, on August 13, 2014.

A tidal wave hits a bank along the Qiantang River on August 22, 2013. 

Spectators are swept by huge waves while watching tides on the Qiantang River on August 15, 2014. 

A paramilitary policeman holds onto a fence as tourists run from tidal waves increased under the influence of Typhoon Dujuan, on the banks of the Qiantang River on September 29, 2015.

Onlookers are swept down a hill by huge waves in Haining, as the seasonal waves surged higher than usual due to the influence of Typhoon Trami, in eastern China's Zhejiang province, on August 22, 2013. 

Onlookers struggle to their feet after  being washed down a hill by huge waves in Haining, China, on August 22, 2013.

More than 660,000 people line the north bank of Qiantang River to watch its annual wonder, the Qiantang River tides, on October 3, 2012. 

Spectators are swept by huge waves while watching tides on the Qiantang River on August 31, 2011.

Visitors run from a wave caused by a tidal bore which surged past a barrier on the banks of Qiantang River, in Hangzhou, China, on August 30, 2015.

Policemen and residents try to stay on their feet as waves from a tidal bore surge over a barrier on the banks of Qiantang River in Haining on August 31, 2011.

Spectators are swept by huge waves brought by Typhoon Dujuan while watching tides of Qiantang River on September 29, 2015. 

Residents run away as waves from a tidal bore surges over a barrier and a vehicle on the banks of Qiantang River on August 31, 2011.

A tidal wave hits a bank along the Qiantang River on August 22, 2013, in Haining, China.

Visitors are hit by a wave caused by a tidal bore on the banks of Qiantang River in Hangzhou on October 28, 2015. 

A man clings to a road sign pole to escape the water from a tidal bore in Hangzhou on September 1, 2015.

Visitors run away from waves from a tidal bore as it surges past a barrier on the banks of Qiantang River, in Hangzhou Zhejiang province, August 25, 2013. Picture taken August 25, 2013.

Mannequins are toppled by the tide as a television crew films the scene along the banks of the Qiantang River in Hangzhou on September 25, 2010. The mannequins act as warning guides to alert tourists of the rising tides.