Rivers are a nice big body of water, that flows into another body of water. They can flow into oceans, lakes, and even seas. There are small rivers, which can be referred to as a pond, or stream, and there are larger rivers. Some common large bodies of rivers are known as the Missisippi River, and the Niles River. There is no definite rules as to what can define a river. A river is a river. Sometimes rivers can flood. This is a natural part of their cycle. Life on the river can be calm as well as harsh. Rivers usually flow from north to south. It sometimes may be able to flow in the opposite direction, but is more common when they flow downhill. Rivers are becoming very useful to the environment. Many others are managed to increase the rate of the flow.