Warfare

Warfare also spread ideas and cultures. One region that was especially vulnerable was Mesopotamia (Tigris and Euphrates River valleys) having no natural land barriers. Time and time again invaders took over the land mixing their culture and ideas with those already there. In time, this region became a rich cultural mix.

On the other hand, the Nile River in Egypt was surrounded by the Sahara Desert. An invasion attempt on Egypt would have been very difficult. Egypt may have been impervious to attack, but it was still a major cultural hearth due to its geographic location.