The Chinese call it the Silver Dragon, and it is the largest tidal bore in the world. The Guiness Book of Records states, 'at spring tides the wave attains a height of 7.5 m and a speed of 24-27 km/h.' In the twelth and thirteenth centuries, suicidal surfers would ride the bore on small planks of wood, in an attempt to placate the dragon's wrath. It has wreaked havoc in the country side, killing many a thousand. It was only in 1988 that the Chinese finally permitted strangers on the Qiantang when the dragon roared.