Cradle of civilization
The concept of a cradle of civilization has a focus where the inhabitants came to build cities, to create writing systems, to experiment in techniques for making pottery and using metals, to domesticate animals, and to develop complex social structures involving class systems.
The Columbia Encyclopedia, in its article titled "Civilization," says that the earliest civilizations developed in the following parts of the world: "Mesopotamia, Egypt, China, India, the central Andes, and Mesoamerica."[11] Since the 1990s, scholarship has defined Norte Chico in the coastal area of present-day Peru as another independent site of civilization.[4]
In the United States and Canada, the AP World History teaches that the six early civilizations as the foundation of human culture are: "Mesopotamia, Egypt, Indus, Shang (or Yellow River valley), Mesoamerica and Andean South America.[12][13] These "civilizations" are also discussed in this article.
Scholars more generally now believe that civilizations arose independently at several locations in both hemispheres.
The rise of dynastic Egypt in the Nile Valley occurred with the unification of Upper and Lower Egypt in approximately 3200 BC, and ended at around 343 BC
Archaeological sites such as Sanxingdui and Erlitou show evidence of a Bronze Age civilization in China. The earliest bronze knife was found at Majiayao in Gansu and Qinhai province dated 3000 BC.
四大古文明的意義並不在時間的先後，而在於他們為現在文明的發源地，亦可以說是一個創造點。
http://zh.wikipedia.org/wiki/%E5%9B%9B%E5%A4%A7%E6%96%87%E6%98%8E%E5%8F%A4%E5%9B%BD
http://en.wikipedia.org/wiki/Cradle_of_civilization