If you were looking for a nice place to settle down in the desert, your short list of requirements might look something like this:
1. Access to a reliable water supply.
2. See number one.
Compare this image of Egypt after dark, captured through the ISS cupola window on November 6, 2017, to any nighttime image of the US or Europe. Electric lights are a telltale indicator of civilization, and this view reveals a population pattern driven by harsh reality. Alexandria and Cairo (left center) are two of the largest cities in Egypt. Their location where the mouth of the River Nile meets the Mediterranean Sea is not accidental. Most of the country’s remaining population lives within a practical irrigating distance of the river, where fertile mud deposited by annual floods produces a narrow band of first-rate farm land.
Some fundamental questions about the Nile, which flows from south to north through a total of eleven African nations, are still open to debate. Although widely favored in a dispute with the Amazon, it may or may not be the longest river in the world. Claims to bragging rights as to the true source of the Nile are also unsettled, with feeder rivers in both Rwanda and Burundi floated as viable contenders.
Science link: https://www.utdallas.edu/geosciences/remsens/Nile/