Asia
The coastal periphery was home to some of the world's earliest known civilizations, each of them developing around fertile river valleys. The civilizations in Mesopotamia, the Indus Valley and the Yellow River shared many similarities. These civilizations may well have exchanged technologies and ideas such as mathematics and the wheel. Other innovations, such as writing, seem to have been developed individually in each area. Cities, states and empires developed in these lowlands.
Ancient Near East
Sumer, located in southern Mesopotamia, is the earliest known civilization in the world. It lasted from the first settlement of Eridu in the Ubaid period (late 6th millennium BC) through the Uruk period (4th millennium BC) and the Dynastic periods (3rd millennium BC) until the rise of Assyria and Babylon in the late 3rd millennium BC and early 2nd millennium BC respectively. The Akkadian Empire, founded by Sargon the Great, lasted from the 24th to the 21st century BC, and was regarded by many as the world's first empire. The Akkadians eventually fragmented into Assyria and Babylonia.