which certainly persisted throughout China's imperial period and arguably continues into the modern age, has its roots in the irrigation systems of the Huang He culture. The Nile settlements grew into the Egypt of the Pharaohs, which endured in one form or another until the Roman conquest three thousand years later. The Tigris-Euphrates societies, collectively referred to as Mesopotamia, gave life to the Sumerian, Akkadian and Babylonian Empires that dominated much of ancient West Asia. Alone of the four, the history of the Indus Valley civilization, called Harappa, is largely unknown, having only been rediscovered in the 1920s. Harappa aside, culture and politics born in all three of the others are major, known influences on societies that thrived millennia after their founding.

To get as specific as possible, even in the narrowest possible sense the classical civilizations of Greece and Rome took concrete influence from the river valley cultures. To start with the obvious, Rome was a river valley culture, based around the Tiber. It was just a late bloomer. But even limiting the question to the four traditional cultures, both Greece and Rome were powerfully affected by the older river valley civilizations. 

Egypt in particular was vital to the classical world. In Greece, Egyptian influence was so prominent that it became commonplace to worship the chief deity of both cultures as a single being: Zeus-Ammon. The influence was sufficient that even after conquering Egypt, Alexander the Great identified himself with Zeus-Ammon to consolidate his power. In Rome, worship of ancient Egyptian deities like Isis often eclipsed the worship of Roman ones and persisted well into the Christian period, with some historians identifying the classic Christian image of Mary with the infant Jesus with the ancient figure of Isis suckling the infant god Horus.

Mesopotamia also had substantial influence on Greece and Rome, primarily through Persia. The Persian Empire encompassed Mesopotamian societies including Assyria, Babylon, and Sumeria, and many customs and much of the culture of imperial Persia has Mesopotamian roots. Persian interaction with Greece is largely portrayed by history as adversarial, and that's not incorrect, but like so many warring societies, each exerted a strong influence on the culture of the other, including clothing, culture, and language. The two cultures were so intertwined that Themistocles, Greek hero of the Persian War, finished his life as a regional governor in the service of the Persian king Artaxerxes II.

In short, in addition to being the earliest examples of what modern people think of as civilization and to being powerful societies that existed for thousands of years and exerted influence for thousands more, the ancient river valley cultures, particularly Mesopotamia and ancient Egypt, were vital in the formation of what we think of as classical Greece and Rome.

There are four main river valley civilizations that changed the path of human existence; these developing regions are referred to as "the cradles of civilization." The four river civilizations are Mesopotamia, the Nile River Valley Civilization, the Indus Valley Civilization, and the Yellow River Valley Civilization.

These civilizations developed the idea of the city-state and what was necessary to make the city-state function. This included religion, social structure, a specialized workforce, a surplus of food, and a writing system.

Mesopotamia (5000–3500 BCE) existed between the Tigris and Euphrates rivers. We can thank them for metallurgy advancements, in particular silversmithing. One Mesopotamian culture, the Sumerians, created the writing system known as cuneiform, which was used to keep track of trade transactions.

The Yellow River Valley Civilization in China consisted of two main dynasties, the Xia (c. 2070–1600 BCE) and the Shang (1600–1046 BCE). While the Xia remains little understood at this point due to lack of archeological evidence, the digs from the Shang dynasty are quite remarkable. Chinese writing developed during this time period and is very similar to the writing system in China today. Bronze weaponry and ritual pieces have been excavated from Shang sites as well.

The development of writing and metalworking can be traced to all four civilizations, which continued to evolve during the Iron Age as these groups expanded and interacted with neighboring peoples.