There are two kinds of tidal bore phenomena in the world: one is at the mouth of the Amazon River in South America; The other is in Haining, on the north bank of Qiantang River in China. Because the estuary from Hangzhou Bay to Qiantang River is trumpet-shaped, the width of the estuary is 100 km, while the upper reaches of Yan Guan River are less than 3 km, but at this time, the river tide is advancing at the speed of 10 m per second. The tidal bore is affected by the sharp contraction of both banks, the water body is flooded and the tidal wave is increasing. If the tide is like a vertical wall, it will form the world-famous haining tide.

The haining tide is twice a day, with the interval between day and night 12 hours. However, due to the influence of the gravity of the moon and the sun, the intensity of tidal bore also changes regularly. Every month from the first day to the fifth day of the lunar calendar, from 15th to 20th, it is a spring tide day, so there are 120 good days to watch the tide in a year. Every year, the eighth day of the eighth lunar month is a traditional "tide-watching festival", and people regard it as the birthday of the "tide god". According to traditional customs, people hold various ceremonies to pay homage to the "tide god", pray for peace and place good wishes. For thousands of years, the wonders of the world have attracted countless people with lofty ideals. Emperor Qianlong went to Haining in the south of the Yangtze River six times; Scholars of all ages, from Zhuangzi, Sima Qian, Bai Juyi and Su Dongpo to Wang Guowei, Lu Xun and Guo Moruo, left over a thousand masterpieces of chanting tides after seeing the grandeur of the world. Great historical figures, such as Sun Yat-sen and Mao Zedong, also expressed their feelings and wrote famous poems. Party and state leaders, such as Yang, Yang, Yang and Yang, have visited the Qiantang River and watched the spectacular Haining tide.

August 18th of the lunar calendar is the best time to watch the famous astronomical tide in Qiantang River. Now I recommend several good places to watch the tide: Changshanmen, Zhangpu Town, Haiyan County, which is 85 meters long and 12.6 meters high. There is a sea pavilion on the hill next to the sluice. Standing in the pavilion, you can see the strange landscape that the tidal bore begins, then the tidal head stands up and presses over the beach and goes upstream.

When the spring tide comes, due to the influence of the silt in the middle of the river, the tidal bore meets and collides from east to south in the big gap area, arousing the iceberg snow peak, and the sound is like thunder, and the scene is thrilling.

The Babao Longtou Corner in the South Longtou Corner of Yan Guan, Haining City is a huge reef protruding from the seawall, forming a small bay here. When the tidal bore comes here, the waves beat on the shore and the raging waves roll, which is called "angry tide".

In the 1960s, a dam with a length of 650 meters and a height of 9 meters was built in the old salt warehouse, one kilometer away from the west Bayi. When the tide collides with the dam, it will rush to the dam along the slope, and then return to the seawall on the river 18 floor, and the water drops will pour down like a rainstorm, which is very spectacular.

In the tide-watching park, "100,000 troops ring the midnight tide". The tide in Shanghai surges during the day, and the night tide is even more thrilling and magnificent. Watching the night tide is usually in Yan Guan Tide Watching Park. At midnight, all is silent. Suddenly, I heard the pounding of hooves coming from the east, which became louder and louder. The black dragon also rose to the surface of the river, smashing the moonlight of the whole river into silver. The river, which was just as calm as a mirror, suddenly became a choppy world. ◆