The Whale Who Wanted to Sing at the Met (1946)
Here's some classic animation for your Monday morning: a 1946 Disney short about an opera-singing whale, entitled The Whale Who Wanted to Sing at the Met. Inspired by experience in his home recording studio, Nelson Eddy voiced all the human (and whale) voices in the film, including multi-voice opera set pieces including sextets (some parts were pitch-shifted to artificially extend his range). Awesome.
Part 2 after the jump.
Warning: there are some dark moments in this part, as with many early Disney cartoons.