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.
Norte Chico civilization
The Norte Chico civilization (also Caral or Caral-Supe civilization) was a complex pre-Columbian era society that included as many as thirty major population centers in what is now the Norte Chico region of north-central coastal Peru. The civilization flourished between the fourth and second millennia BC, with the formation of the first city generally dated to around 3500 BC, at Huaricanga, in the Fortaleza area. It is from 3100 BC onward that large-scale human settlement and communal construction become clearly apparent, which lasted until a period of decline around 1800 BC. Since the early 21st century, it has been established as the oldest known civilization in the Americas.