Introduction to Snake Bend: The rare Snake Bend landscape has ninety-nine bends in the Yellow River. The five big bends formed in Yanchuan are collectively called Hequ, and their scientific name is Snake Bend. Snake curves are geological landforms that are meandering like snakes and are formed by river erosion. The Yanchuan Yellow River Snakes are the largest, best and densest group of snakes in the mainstream rivers of China. It is a rare sight.