"Death's-Head Revisited"
A deeply satisfying (if only it were real) episode of The Twilight Zone wherein Nazi SS guy goes back to the Dachau Concentration Camp, and the ghosts of all the people he killed inflict upon him the horrors that were inflicted upon them. And when the doctors are taking him away at the end 'cause he's gone all batshit, the one asks why they haven't torn down the concentration camp, and this is what Rod Serling says (because he's awesome like that):
"...All the Dachaus must remain standing. The Dachaus, the Belsens, the Buchenwalds, the Auschwitzes-- all of them. They must remain standing because they are a monument to a moment in time when some men decided to turn the Earth into a graveyard. Into it they shoveled all of their reason, their logic, their knowledge, but worst of all, their conscience. And the moment we forget this, the moment we cease to be haunted by its remembrance, then we become the gravediggers. Something to dwell on and to remember, not only in the Twilight Zone but wherever men walk God's Earth."
"...All the Dachaus must remain standing. The Dachaus, the Belsens, the Buchenwalds, the Auschwitzes-- all of them. They must remain standing because they are a monument to a moment in time when some men decided to turn the Earth into a graveyard. Into it they shoveled all of their reason, their logic, their knowledge, but worst of all, their conscience. And the moment we forget this, the moment we cease to be haunted by its remembrance, then we become the gravediggers. Something to dwell on and to remember, not only in the Twilight Zone but wherever men walk God's Earth."