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.
Olmecs
The Olmec may have been the first civilization in the Western Hemisphere to develop a writing system. Symbols found in 2002 and 2006 date from 650 BCE and 900 BCE respectively, preceding the oldest Zapotec writing found so far, which dates from about 500 BCE.