A guy meets the ghost of Hilter in season 4 episode 4 of the twilight zone. the ending is like this narrated by Rod Serling:

“Where will he go next, this phantom from another time, this resurrected ghost of a previous nightmare – Chicago? Los Angeles? Miami, Florida? Vincennes, Indiana? Syracuse, New York? Anyplace, everyplace, where there’s hate, where there’s prejudice, where there’s bigotry. He’s alive. He’s alive so long as these evils exist. Remember that when he comes to your town. Remember it when you hear his voice speaking out through others. Remember it when you hear a name called, a minority attacked, any blind, unreasoning assault on a people or any human being. He’s alive because through these things we keep him alive.”