4. Augrabies Falls
Situated on Orange River in South Africa, this waterfall can be both your friend and enemy. It is 240 meters high, flowing against granite stones. Some time, it can release four times of water volume to that of Niagara, which can be very dangerous for swimming enthusiasts. However, it also slows down, even until very little water is left, for you to feel its spirit.
Image Credit: dragonfly