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.
Prehistory
Human prehistory is the period between the use of the first stone tools 3.3 million years ago by hominins and the invention of writing systems. The earliest writing systems appeared 5,300 years ago, but it took thousands of years for writing to be widely adopted and it was not used in some human cultures until the 19th century or even until the present. The end of prehistory therefore came at very different dates in different places, and the term is less often used in discussing societies where prehistory ended relatively recently.