First, Andrew Johnson was never impeached. He was tried for treason after he fired Edwin M. Stanton, the secretary of war, from office. He was extremely close to being impeached—just 1 vote short. Radical republicans attempted this because they disagreed with his reconstruction plan. Make sense?
Auschwitz was an Extermination camp for Jews. It was the largest camp built. So the answer for said question is, Auschwitz. Please feel free to ask anymore WWI and WWII questions!