This 1939 MGM cartoon directed by Academy Award-winner Hugh Harman was released at the dawn of the second world war. In this animated reel, the war is over and mankind has been wiped out.
According to Harmon's obituary in the New York Times, the film was nominated for a Nobel Peace Prize, though it is not listed in the official Nobel database. Either way, it is a classic cartoon from the golden age of animation and worth your time.
All that, and singing squirrels.
