A waterfall is a physical geological feature that occurs where a river or stream flows over a vertical drop or a series of steep drops in the streambed. These formations are typically created through processes of differential erosion, where a layer of hard, resistant rock underlies softer rock layers, leading to undercutting and eventual collapse of the weaker material. The erosive power of the falling water contributes to the shaping of the surrounding landscape, often forming plunge pools at the base and potentially creating gorges or canyons over immense timescales. The height and rate of recession of a waterfall are governed by the varying resistance of the bedrock and the sustained force of the kinetic energy exerted by the moving water mass.