The Holocaust was the state-sponsored, systematic persecution and annihilation of European Jews by Nazi Germany, and its collaborators between 1933 and 1945.
Prison camps(concentration camps) held Hitlers "enemies" and basically the people he didn't want(Jews). At prison camps all hostages would be worked until death or killed if the officers there decided they didn't want them. From 1933-1939 million of Jews were held here with little food or water. Prisoners not just worked for just anything they had to build things FOR the Nazi's.
The U.S. involvement with "the War"
Slightly more than half of the U.S. immigrants were Jewish in 1939-1940. The U.S. helped keep 200,000 Jews safe from 1933-1945.The U.S. helped a lot of people during the war. Eventually,the U.S. would help to stop the Nazis.
As the Nazi government is losing their "good look" they need to find a way to get people following them again. The government is basically lying to get people to give them support again. They said they were the victim and that they were the ones who were defending themselves. This was all of course a lie, but unknown by the public.