Tigris–Euphrates river system through the central plain and combine at Al-Qurnah to form the Shatt al-Arab and discharge into the Persian Gulf. The region has historical importance as part of the Fertile Crescent region, in which civilization is believed to have first emerged. The ecoregion is characterized by two large rivers, the Tigris and Euphrates. The rivers have several small tributaries which feed into the system from shallow freshwater lakes, swamps, and marshes, all surrounded by desert. The hydrology of these vast marshes is extremely important to the ecology of the entire upper Persian Gulf. Historically, the area is known as Mesopotamia. As
Watching the River Flow composing protest songs. For Shelton, who noted the promotional photo for "Watching the River Flow" depicting Dylan looking through a camera, the track expressed Dylan's wish just to be an observer, and not a political activist. Author Seth Rogovoy similarly interpreted the song as Dylan's desire to ignore politics and avoid getting involved in people's disputes. The line "[This ol' river] keeps on rollin', though/No matter ... which way the wind does blow" has been heard by writers Peter Vernezze and Carl J. Porter as evidence of Dylan's conviction that "the river of time, the flow of facts, in reality