What has a mouth but doesn't eat, a bed but doesn't sleep, and runs but has no legs?

It's a clever description of a river, a natural flowing watercourse found all over the world. The "mouth" refers to the place where a river discharges its water, typically into a larger body of water like a sea, lake, or ocean. These areas are often dynamic, with sediment carried by the river being deposited, sometimes forming intricate deltas or wide estuaries.

The "bed" of a river is the ground or channel over which the water flows, a dynamic landscape constantly shaped by the moving water. While a riverbed provides a foundation (Review) for aquatic life, it certainly doesn't sleep. Instead, the river "runs" continuously due to the force of gravity, pulling water from higher elevations, like mountains and hills, downstream towards lower ones.

Rivers are vital arteries of our planet, essential sources of freshwater that have profoundly influenced human history and continue to support diverse ecosystems. They provide drinking water, enable irrigation for agriculture, facilitate transportation, and even generate hydropower. These powerful natural forces also sculpt landscapes through erosion and deposition, constantly changing the face of the Earth.