Enjoy Carmen Miranda and Don Ameche in the opening number of That Night in Rio, one of roughly 978 early '40s Fox musicals set in South America. The number goes on too long, but the Harry Warren tune is a good one.
One thing to watch for is the shot around the middle of the number, just after the singing ends and we cut to the band members, all dressed in red. Of course you can't get the full impact online (or even on the less-than-spectacular DVD transfers), but it's a great example of how Fox's cinematographers used Technicolor: cutting to a screen full of red, after a sequence without very much red in it, has a nearly physical impact. People have said that a Fox Technicolor movie is almost like 3-D; the colors leap off the screen, and one reason for that is that photographers like Leon Shamroy and Ray Rennahan (the two credited cinematographers on this film, though I don't know which one did this scene -- that bathed-in-red shot looks like Shamroy, though) knew how to save certain colors for maximum effect.
Another observation: I sometimes wonder what Don Ameche could have done if he'd been given a real movie musical to star in, in his prime. He made a lot of films that were technically musicals, but Fox's musicals (as I've written in an earlier post) had very little singing or dancing that was even marginally related to the story; usually the films are about entertainers, and Ameche or Grable or Faye or whoever sings a song on a stage, playing a nightclub performer. Ameche did very well in the '50s when he went to Broadway to do musicals -- like Cole Porter's Silk Stockings. But in Hollywood, a popular leading man who could act and sing would have been a real asset to an actual "book" musical if the studio had given him one.