Question: Why was there concentration camps? 

Answer: Hitler and his henchmen decided to rid the "Fatherland" of Germany and its conquered neighbors of the disabled, disfigured, transient, gypsy and jewish populations.  The concentration camps were a place where people were efficiently shipped to take part in this ethnic cleansing or Xenocide campaign.  The basic idea was to remove them from the public eye, use them for labor where needed, and kill the less useful.    In other words, it was a coldly calculated means of mass murder and enslavement, and is one of the worst examples of human behavior in recorded history.
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