Three Little Pigs
The Three Little Pigs each build a house of different material. The Big Bad Wolf comes along and blows away the straw and stick homes, but is unable to destroy the house of bricks.
The most commercially successful cartoon short ever released and a genuine cultural event. Its song became an unofficial anthem of Depression-era resilience, played and sung well outside cinemas, and the film ran in some theatres for months. It also marked a turning point in the craft: the three pigs look identical but move and act completely differently, which was the studio proving that personality could come from performance rather than design. Almost every animation studio changed direction after this.
The wolf's peddler disguise in the original 1933 version was an antisemitic caricature; Disney redrew and redubbed the sequence in later reissues, and circulating prints normally show the revised version.