A natural phenomenon occurs every year attracts thousands of tourists annually

 A natural phenomenon occurs every year in China's Qiantang River attracts thousands of tourists annually
Every year in late summer, there is a river attracts thousands of tourists to see the wave of beautiful waves that arrive in some cases to 9 feet high.
It Qiantang River in China every year, which is known as a tidal wave and the islands in the world, which reaches a speed of 40 kilometers per hour.
There is a simple explanation for this phenomenon, namely that the strength of the tides is increasing in the first and fifteenth of every lunar month, and this is due to that these days the sun and the moon and the earth in a straight line and the overall strength of the attraction between objects increase the power of the tides!! .
Despite the beauty of this wave that sometimes incidents occur and cause of death for a number of people.