The tidal waves at the estuary of the Qiantang River is a wonder of the world, known since ancient times for their tremendous momentum and magnificent sight. Bore watching began 2,000 years ago during the Han and Wei dynasties. High tidal waves appear in the Qiantang River between the first and fifth days and between the 15th and 20th days every month but those appearing around the 18th of the eighth lunar month are the highest. On the occasion, several hundred thousand people throng to watch tidal waves surging in the river. Xiaoshan in Hangzhou is a good place to watch the tidal waves but the best spot is Yanguan in Haining County 45 kilometers from Hangzhou. Many people prefer to watch the tidal waves from different spots.