1.This "fire" was actually apple juice spewing out of Dorothy's shoes; the film was sped up to make it look like fire.
2.The Cowardly Lion's facial makeup included pieces of a brown paper bag.
3.The steam shooting from the Tin Man's cap startles Toto, who runs out of the shot.
4.Judy Garland couldn't stop giggling while filming the scene in which Dorothy slaps the Cowardly Lion. The director, Victor Fleming, took her aside and slapped her. She returned to the set and filmed the scene in one take.
5.The scarecrow face prosthetics that Ray Bolger wore left a pattern of lines on his face that took more than a year to vanish.
6.Most of the Wicked Witch's scenes had to be edited or cut all together after they were deemed too frightening for children.
7.The "oil" that was used to lubricate the Tin Man was chocolate syrup. (Real oil didn't photograph well.)
8.Toto's real name was Terry.
9.The Cowardly Lion was originally going to be played by Jackie the MGM Lion, with lines dubbed in by an actor, until Bert Lahr came up for the part.
10.Professor Marvel might be an asshole for never returning Dorothy's photo of Auntie Em.
11.Whoa: Liza Minnelli, daughter of Judy Garland, was married to Jack Haley Jr., the son of Jack Haley, who played the Tin Man.
12.You can clearly see the trap door open in the scene where the Wicked Witch departs Munchkinland.
13.The Scarecrow was unable to say the correct Pythagorean Theorem (right after he got his brains), so after multiple attempts, the director simply selected the best take and used it.
14.Dorothy's white dress was actually pink, which was easier to shoot in Technicolor.
15.When Dorothy asks the Wizard who he is, she has Toto in her arms, and you can see her taking the string from around his neck where the curtain was attached.
16.The Tin Man's pants wrinkle throughout the movie, a dead giveaway that they're not really made of tin.
17.Margaret Hamilton's makeup was toxic and could not be ingested, so she lived almost entirely on a liquid diet during filming.