Why did civilization develop in the Fertile Cresent?

The ascent of 'civilized' society had much to do with the change from hunting and gathering for food to agriculture. As it happens, the first known people to make that change were Natufian tribes who lived in the area that is now Israel and Lebanon. The sedentary lifestyle, the switch to agriculture and the building of villages and later on of cities spread from there, and into the fertile crescent for the very reason that is WAS fertile and very suitable for agriculture.