Geographically-speaking, the Levant boasts some of the most diverse natural features in the Arab World. The Syrian Desert, a 200,000-square-miles wide rocky and flat desert, occupies the center of the Levant and is considered a continuation of the Arabian Desert. To its east lies Mesopotamia, fertile agricultural plains traversed by two rivers: Euphrates and Tigris. Both rivers originate from Anatolia and are fed by numerous tributaries; the entire river system drains a vast mountainous region. In the western Levant, hilly terrains and mountain ranges rise parallel to the Mediterranean coastline from the north to the south encompassing the: An-Nusayriyah Mountains, Lebanon Mountains, Galilee Hills, Samarian Hills, and Judaean Mountains. This mountainous barrier receives a substantial amount of precipitation and snow, and enjoys a thick forest cover, mainly Mediterranean woodlands and forests. Between the Mountains and the shoreline extends a densely populated narrow and fertile coastal plain.