Can all falling water be considered a waterfall? Not exactly. To be deemed a waterfall a segment must be at least five feet high. To further qualify, according to Milestone Press, the waterfall must come from a river, creek, or stream that provides water at least annually.

Geologically, a waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. This usually occurs when a river courses over a top layer of resistant bedrock before falling onto a layer of softer rock, such as shale, which erodes more quickly. As the softer rock is worn away, it creates a steep ledge or cliff. Over time, the force of the falling water creates a "plunge pool" at the base through a process called hydraulic action. To be officially classified as a waterfall rather than just a "rapid" or a "cascade," there must be a distinct vertical element. While there is no single universal height requirement, many geological surveys and organizations use a minimum height of 5 to 20 feet to distinguish them from other water features. The largest waterfalls, like Angel Falls, are formed by dramatic tectonic shifts or glacial activity that creates a massive "hanging valley," allowing the water to plummet thousands of feet into the landscape below.