A concentration camp is a Nazi camp for Jews, handicapped, Poles, communist, and gypsies. The camps were used to hold innocent people, and starved them, killed them or made them work for nothing, and many other ways of torture. Many Jews and other people died from various things such as starvation and tourture.
http://webpage.pace.edu/nreagin/tempmotherhood/spring2002g/suffering%20typhus.jpg