A waterfall is a stretch of river where, due to a strong unevenness in the bed or riverbed, the water falls vertically as a result of gravity. Waterfalls are considered one of the most beautiful phenomena in nature. Some waterfalls are used to generate hydroelectric power.

Waterfalls are dynamic systems that vary with the seasons and the years, although the latter is only perceptible on a geological scale. They have different shapes (for example, if their fall is vertical or if it follows a steep slope, etc.), determined by the volume of water, the height of the fall, the width of the bed and the shape of the walls between which the liquid flows, depending on the type of rock and the different layers in which they are laid.

Among the most famous waterfalls in the world are the Iguazú Falls – composed of 275 waterfalls of different heights located between Argentina and Brazil -, the Niagara Falls – located on the border between the United States and Canada and with a flow that reaches 11. 000 m³/s -, the Yosemite Falls – in California, with 739 m of fall, well known for its beauty – and the Angel Falls – in Venezuela, which with a height of 979 m (807 m of uninterrupted fall), is the highest waterfall in the world.