What was the purpose of Nazi extermination camps?

The purpose of the Nazi extermination camp was to kill all the jews they were able to catch.

The purpose behind the extermination camps was to basically as the name states, exterminate people who the Nazis did not see fit to live, mostly people of Jewish origin and who they saw as being less pure than the ideal German should have been. Anyone who was seen to be as Jewish, with dark hair and dark eyes, or people that did not have "Aryan" characteristics we rounded up. Jews, Gays, Ethnic Poles, homosexuals, Jehovah's Witnesses, and Spanish Republicans were all known to be targets of the Nazi encampments and killed within the death camps. In just one extermination camp alone, it was estimated that over 1.5 million people were killed.