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.
History of the Maya civilization
The history of Maya civilization is divided into three principal periods: the Preclassic, Classic and Postclassic periods; these were preceded by the Archaic Period, which saw the first settled villages and early developments in agriculture. Modern scholars regard these periods as arbitrary divisions of chronology of the Maya civilization, rather than indicative of cultural evolution or decadence. Definitions of the start and end dates of period spans can vary by as much as a century, depending on the author. The Preclassic lasted from approximately 2000 BC to approximately 250 AD; this was followed by the Classic, from 250 AD to roughly 950 AD, then by the Postclassic, from 950 AD to the middle of the 16th century. Each period is further subdivided: