Oz: the Great and Powerful crashes into movies theaters today harder than Dorothy’s farmhouse killed a witch. Brush up on your Oz knowledge before you go see the movie.

• Published in 1900, The Wonderful Wizard of Oz is the first Oz book, and the basis for the classic 1939 film, but it’s not the first thing author L. Frank Baum ever published. Decades earlier, he was a chicken farmer, specializing in Hamburgs, a rare German breed. In 1886, Baum published a chicken raising guide called The Book of the Hamburgs: A Brief Treatise Upon the Mating, Rearing, and Management of the Different Varieties of Hamburgs. (The Oz novels are much more entertaining.)

• In 1905, Baum announced his intentions to funnel his wealth from the huge sales of The Wonderful World of Oz into an Oz-themed amusement park on Pedloe Island, off the coast of California. Baum said he planned to both live there, and hire an all-children advisory board to consult on the park’s operations. One problem: there’s no such place as Pedloe Island. (It was probably a practical joke.)

• The Oz series has been adapted for the screen many times, none more famous than the 1939 MGM version starring Judy Garland, Burt Lahr, and Ray Bolger. A movie that popular is bound to generate some urban legends. You’ve probably heard the one about how if you look closely you can see a suicidal “Munchkin” actor hanging from a tree, or that the film syncs up with Pink Floyd’s Dark Side of the Moon album. But one that is true: there’s a lost musical number, “The Jitterbug.” In the scene, the Wicked Witch of the West sends the magical bugs after Dorothy and her friends. The producers cut the scene because they felt it would date the film.

• In 1985, Walt Disney Pictures released Return to Oz, an unofficial sequel to the 1939 film, loosely based on the second and third novels in Baum’s series. The big-budget extravaganza flopped and it’s now considered one of the most frightening family films ever made. Among the scary scenes: Dorothy gets sent to a hospital for electric shock treatments, she fights a witch with a gallery of removable heads, and she watches her friends get turned into ornaments. The farm girl also spends much of the film hanging out with a talking chicken and a freaky character with a gigantic pumpkin for a head.