Which is considered the oldest civilization in the world?

Mesopotamia is a historical region in southwestern Asia where the world’s earliest civilization developed. The name comes from a Greek word meaning “between rivers,” referring to the land between the Tigris and Euphrates rivers, but the region can be broadly defined to include the area that is now eastern Syria, southeastern Turkey, and most of Iraq. The region was the center of a culture whose influence extended throughout the Middle East and as far as the Indus valley, Egypt, and the Mediterranean.

The Sumerians and Akkadians originating from different areas in present-day Iraq, dominated Mesopotamia from the beginning of written history (c. 3100 BC) to the fall of Babylon in 539 BC, when it was conquered by the Achaemenid Empire. It fell to Alexander the Great in 332 BC, and after his death, it became part of the Greek Seleucid Empire. Later the Arameans dominated major parts of Mesopotamia.

Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC. It has been identified as having "inspired some of the most important developments in human history.