What effects did Columbus have on today's world?

There are
two different ways to answer this question.

First, we can say that
Christopher Columbus had a huge impact on todays world.  It was through his voyages that the New
World was discovered.  This led to many very important changes.  First, it led to the
destruction of large populations of Native Americans.  Large percentages of these people died
from diseases and other causes related to the Europeans.  Those who survived generally had their
societies destroyed and came to be subordinate members of societies dominated by Europeans. 
Second, it led to the development of African slavery.  The discovery of the Americas led
to...