River

A river is a natural landmark of flowing, typically fresh water that flows from lakes and oceans.

History
Many early civilizations were built alongside rivers, such as the ancient Egyptians, who built the Pyramids on the Nile. In Equestria, settlements such as High Desert created artificial rivers in order to presumably help grow their crops and also serve as natural barriers against threats like Lumber Bears. The great city of Canterlot was built on a mountain overlooking a long, flowing river.