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The original concept for the Wicked Witch of the West was to have her resemble a strikingly beautiful woman much in the same way the Evil Queen in Snow White and the Seven Dwarfs (1937) was conceived. Producer Mervyn LeRoy originally cast MGM beauty Gale Sondergaard in the role as a sleek, sexy Wicked Witch of the West. However, the presence of a sexy Wicked Witch left a large plot hole within the script, for it played against the idea that bad witches were ugly. Convinced that the point was important, LeRoy retested Sondergaard as an ugly witch. Unhappy with how she looked in the make-up, she immediately declined the role and was replaced with Margaret Hamilton. The "sexy Wicked Witch" idea was revived for more recent Oz reimaginings such as Tin Man (2007), Dorothy and the Witches of Oz (2011),Oz the Great and Powerful (2013), and Emerald City (2016) - in some of these, the Wicked Witch is ugly but can maintain a beauty glamor as a disguise.
Many shots were trimmed down or edited out of the film because they were too intense for families and children. In particular, one deleted shot shows the tornado completely enveloping the farmhouse. Also, later in the film a lot of The Wicked Witch of the West's scenes were either trimmed or deleted entirely, as Margaret Hamilton's performance was thought to be too frightening for audiences.
When the wardrobe department was looking for a coat for Frank Morgan (Professor Marvel/The Wizard), it decided it wanted one that looked like it had once been elegant but had since "gone to seed". They visited a second-hand store and purchased an entire rack of coats, from which Morgan, the head of the wardrobe department and director Victor Fleming, chose one they felt gave off the perfect appearance of "shabby gentility". One day, while he was on set in it, he idly turned out one of the pockets and discovered a label indicating that it had been made for L. Frank Baum. Mary Mayer, a unit publicist for the film, contacted the tailor and Baum's widow, who both verified that it had at one time been owned by the author of the original "Wizard of Oz" books. After the filming was completed, it was presented to Mrs. Baum.
Margaret Hamilton, a single mother, got into an argument with the studio over guaranteed time to work, only agreeing to take the role of the Wicked Witch three days before filming. Ironically, although she finally got an agreement for five weeks of work, she ended up working on the film for three months.
Judy Garland found it difficult to be afraid of Margaret Hamilton, because she was such a nice lady off-camera.
The iconic ruby slippers are now at the Smithsonian Institution's National Museum of American History, and so popular that the carpet in front of them has had to be replaced numerous times due to wear and tear.