Final answer:
The region that encompasses Mesopotamia, Syria, Lebanon, and Egypt is known as the Fertile Crescent, which is marked by its crescent shape and historical significance as one of the earliest sites of civilization.
Step-by-step explanation:
The region that encompasses Mesopotamia, modern-day Syria, Lebanon, and Egypt is known as the Fertile Crescent. This label comes from the distinct crescent shape that this fertile area makes on a map, which extends from the Persian Gulf through the Tigris-Euphrates river system in present-day Iraq and westward to the Nile in Egypt. The Fertile Crescent is famed for witnessing the development of early civilization within its bounds around the fourth millennium BCE, particularly amongst the city-states of Sumer in Mesopotamia.
As one of the cradles of civilization, Mesopotamia between the rivers Tigris and Euphrates, known also as the land between the rivers, saw the rise of some of the world's earliest urban centers and is now what comprises parts of Iraq and western Iran. Cities like Ur, Babylon, and Nineveh thrived due to the region's ability to control water through irrigation systems, contributing to their success and the overall cultural and technological advances of the time.