A waterfall is a sudden drop of water from a mountain wall or riverbed. It looks like a white cloth hanging from a distance. In geology, the phenomenon of a river falling vertically from a high altitude when it flows through faults, depressions, etc. is known as a waterfall.

A waterfall is a sudden vertical drop of a flowing river and is a major interruption in its flow.

For the most part, rivers smooth out unevenness in their path through erosion and silting processes. After some time, the profile of the river will form a smooth arc. The river is steepest at its source and mildest at its mouth. The waterfall interrupts this arc and shows the progress of the erosion process.

In some cases, the location of the falls recedes upstream as cliffs or steep ridges are washed by the current. In other cases, the erosion tends to go deep down and diagonally cut the entire section of the river that contains the waterfall.

Over time, the combination of these factors makes it inevitable that any waterfall that may have formed will disappear.

The energy of the river will eventually produce a relatively smooth, concave upward profile. Even in the absence of rubble as a tool for river erosion, the amount of energy that can be used to erode the base of a waterfall is enormous.

The cliffs will constantly collapse under the powerful impact of the water, causing the waterfall to retreat upstream and reduce its height, eventually causing the waterfall to disappear.

Angel Falls is a waterfall on the Charan River, a tributary of the Caroni River, in the Guyana Plateau of Bolívar State, Venezuela. With a drop of 979 meters (3,212 feet), it is the tallest waterfall in the world. The base is 150 meters (492 feet) wide.

In the upper part of the Congo River in Africa, many waterfalls form the Kisangani Falls, the longest waterfall in the world. These waterfalls are mainly distributed along the 100-kilometre-long river, and they range in size from large to small. Seven of the falls are large, with drops of up to 50 meters. The largest one is 800 meters wide.

Kisangani Falls is a group of waterfalls, not remarkable for its width as a waterfall. The longest single waterfall is Iguazu Falls, which is 4,000 meters wide, a beautiful waterfall. Iguazu Falls are the largest waterfall in South America. It is located on the border between Argentina and Brazil and is shared by both countries. It attracts millions of tourists every year.