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.
Ancient history
Prehistory is the period before written history. The early human migrations in the Lower Paleolithic saw Homo erectus spread across Eurasia 1.8 million years ago. The controlled use of fire occurred 800,000 years ago in the Middle Paleolithic. 250,000 years ago, Homo sapiens (modern humans) emerged in Africa. 60–70,000 years ago, Homo sapiens migrated out of Africa along a coastal route to South and Southeast Asia and reached Australia. 50,000 years ago, modern humans spread from Asia to the Near East. Europe was first reached by modern humans 40,000 years ago. Humans migrated to the Americas about 15,000 years ago in the Upper Paleolithic.