How did geography both help and hinder the peoples of Africa?

2 answers

http://wiki.answers.com/Q/How_does_the_physical_geography_of_Africa_affect_the_people_that_live_there
There are books on this.

Think about the Desert.
Think about the Cape of Good Hope
Think about the Congo River
Think about Horn of Africa
Think about the effect of the Nile river

What did these to civilizations?