Directed by: Victor Fleming
Starring: Frank Morgan, Judy Garland, Billie Burke, Ray Bolger, Bert Lahr, Jack Haley, Margaret Hamilton
Continuity mistake: When the Wizard is in the balloon, he raises his top hat pointing in an 11 o'clock direction. A frame later it's pointing in a 9 o'clock direction.
Continuity mistake: When Dorothy and the Scarecrow find the Tin Man and oil his mouth, between shots, the leaves on the Tin Man's shoulders change.
Continuity mistake: When Dorothy slaps Lion on the nose for chasing Toto and shouts, "Shame on you!" in the wide shot, we see Dorothy's right arm with no mark on her skin. It then cuts to the medium shots, and there's an inexplicable long, thin blue mark (it's not a loose thread) on Dorothy's arm near her elbow, while she's holding Toto. This blue mark vanishes in the wide shot when she puts Toto down, and Lion begins to sing. (00:50:25)
Trivia: The "tornado" was a thirty-five foot long muslin stocking, photographed with miniatures of a Kansas farm and fields.
Question: Did Dorothy really go to Oz or was it a dream? Because, in return to Oz at the end, she sees Ozma (the good witch in her mirror) or was that just her imagination/a dream too?
Answer: Return to Oz was not a direct sequel to the 1939 film. One was developed by Disney and the other by MGM. Return to Oz is actually an adaptation-fusion of the second and third Oz books, that contains elements from the 1939 film (like the Ruby slippers and the Oz/Kansas counterparts) because that's what people are most familiar.
Answer: In the film it's left ambiguous. At the end it's strongly implied that she was dreaming. The characters she meets all look like people she actually knows. In the original book, she actually went to Oz.