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.
Cradle of civilization
The earliest signs of a process leading to sedentary culture can be seen in the Levant to as early as 12,000 BC, when the Natufian culture became sedentary; it evolved into an agricultural society by 10,000 BC. The importance of water to safeguard an abundant and stable food supply, due to favourable conditions for hunting, fishing and gathering resources including cereals, provided an initial "wide spectrum economy" that triggered the creation of permanent villages.