Which civilization was located between two rivers the Euphrates and the Tigris?

Mesopotamia literally means "(Land) between rivers" in ancient Greek. The oldest known occurrence of the name Mesopotamia dates to the 4th century BC, when it was used to designate the land east of the Euphrates in north Syria.

Later it was more generally applied to all the lands between the Euphrates and the Tigris, thereby incorporating not only parts of Syria but also almost all of Iraq and southeastern Turkey. The neighbouring steppes to the west of the Euphrates and the western part of the Zagros Mountains are also often included under the wider term Mesopotamia. A further distinction is usually made between Upper or Northern Mesopotamia and Lower or Southern Mesopotamia.