What natural resources did the four early civilizations (Mesopotamia, Egypt, Rome, and Greece) share?
   Sarah, 13, Web post

Dr. dig responds:

This is a huge question, and one which still puzzles archaeologists! Basically all the civilizations which you mentioned, plus others (in the Indus Valley and China, for example) developed in river valleys. It seems that access to a reliable water source is the key to successful development. Water allows the development of agriculture, and a regular supply of food allows communities to flourish and grow rich. Trade then allows further development.