BLACK ORPHEUS [or ORFEU NEGRO in Portuguese] (1959), directed by Marcel Camus.
I've seen this movie several times by now and no doubt will again. What gets you going from the first minute is the beat of the music that's in a frenzy. Then the constant movement of the actors to the beat. And then it's two boys--I wish I could find their names, because they're the ticket, especially the one boy who follows Orfeu on his tragic enterprise--and you see the adult characters through their eyes. For those boys, everything is possible. It is absolutely necessary that someone play the guitar each morning so the sun may rise. This is just the truth as they see it.
This movie won all kinds of awards when it came out. And it popularized the Carnival in Rio de Janeiro for the rest of the world. And no doubt that's what changed the celebration from what we see in the movie to what I've seen in Rio myself in recent years.
Everyone owes it to themselves to see this movie at least once in their life.