Indus River peoples had trading contacts with Mesopotamia, but they developed a distinctive alphabet and artistic forms. This civilization was so successful because of its location allowing the people to trade easily with other civilizations.
To understand history, it is important that you understand how "time" periods are denoted and how a "civilization" is different from that of a "non-civilized" culture. Sumerian political structures stressed tightly organized city-states, ruled by a king who claimed divine authority.
Mesopotamians have contributed to many things like war; the Mesopotamians fought for security and believed that they could defend themselves by expanding into great areas.
Homo erectus appeared as early as , years ago. Egyptian civilization emerged in northern Africa along the Nile River by about B. These developments of architecture were copied throughout the world and are still present to this day.