Answer:
The ancient civilizations of Mesopotamia and Egypt were both facilitated by rivers that ran in their midst. The Euphrates, Tigris, and the Nile deposited silt along riverbanks which made the adjoining land extremely fertile. This led to the development of cities like Ur and Eriku in Mesopotamia, and Thebes in ancient Egypt. In Egypt, the Nile served as a means of transportation and also provided protection from enemies because its marshy deltas made invasion almost impossible.