Opened in 1937, Buchenwald was a Class II forced labor camp, intended for the imprisonment of condemned criminals and captured anti-fascist resistance fighters who were considered to be beyond rehabilitation. In practice, this included religious and political prisoners, Roma and Sinti, Freemasons, Jehovah's Witnesses, criminals, homosexuals, and prisoners of war. About 240,000 passed through the camp during it's 8 year existence, a quarter of them died from starvation, malnutrition, disease, beatings, medical experiments, or execution.  Link