Over thousands of years, the waterfall has eroded its crest and slowly moved upstream. It currently appears to be two waterfalls most of the time, but when the river is swollen due to summer rains can form one fall again. In Vietnamese, the two falls are considered as two parts of one waterfall with the sole name Bản Giốc. The two parts are thác chính (Main waterfall) and thác phụ (Subordinate waterfall). Chinese texts sometimes name both of the water falls as Détiān Falls (
Chinese: 德天瀑布) on the Chinese side. The waterfall drops . It is separated into three falls by rocks and trees, and the thundering effect of the water hitting the cliffs can be heard from afar. It is currently the 4th largest waterfall along a national border, after
Iguazu Falls,
Victoria Falls, and
Niagara Falls. Somewhat nearby is the long by wide Tongling Gorge (Tōnglíng dàxiágǔ 通灵大峽谷 "Tongling Grand Canyon") in
Baise City (百色市),
Guangxi province, accessible only through a cavern from an adjoining gorge. Rediscovered only recently, it has many species of
endemic plants, found only in the gorge.
Geology The waterfalls are located in an area of mature
karst formations where the original
limestone bedrock layers are being eroded. Numerous streams spring from underground fissures along the lower levels of the area. The waterfalls have multiple drops, from bedrock layer to layer, which shows the multiple depositions of sediments of different hardness which formed the terrain over millions of years. ==History==