What Could Have Been/Theme Parks

Examples of What Could Have Been in Theme Parks include:

Disney

 * The Haunted Mansion went through several different ideas. Early concepts included a hangout for horror-themed Disney villains, like the Lonesome Ghosts and the Headless Horseman, having a Raven narrate the ride (abandoned when it was decided the Ghost Host would work better), and a Hatbox Ghost which carried around a severed head as a character (ditched due to the Imagineers deciding it didn't look good enough). Other concepts from the 1950s included several much darker walkthrough attractions, a version where Walt himself narrated, and several very long illusions including a ghost flooding a room.
 * There were many locations Disney was going to originally build Disneyland before he decided to locate in California. One of the places he really had his heart set on was none other than... Flagstaff, Arizona (no, really). He loved the weather the place got during the summer, but then he came and visited during the winter, felt the harsh snowy weather, and subsequently changed his mind.
 * Originally, Disney's second theme park was going to be in St. Louis, Missouri. Although legend says that the mayor of St. Louis mocking Walt's plans to run a resort without liquor doomed the project, it was actually the city's unwillingness to foot part of the bill that killed it. With Disney World already being in the beginning stages at that time, Disney simply couldn't afford both.  So the smaller St. Louis park was canceled.
 * At Walt Disney World in Florida, the Western River Expedition was intended as the Wild West version of Pirates of the Caribbean and was to be exclusive to the park, thus making the California park the only one with the pirates. But early visitors to the Magic Kingdom were upset that Pirates of the Caribbean wasn't included in the lineup, so getting a Florida version of Pirates up and running became top priority, and the new ride never came to pass.
 * Several more countries were considered for Epcot's World Showcase, including a country from Africa. This one was scrapped because the only country willing to back it was South Africa, which was under apartheid in the 1980s. Two years after the park opened, Morocco was added to the lineup.
 * Scrapped attractions for World Showcase included boat-based rides for Germany and Italy. Meet the World, an Audio-Animatronic show retelling the history of Japan, made it as far as its show building going up—but since it glossed over World War II Disney executives feared it would offend Americans (especially veterans). The show did successfully make it into the original Tokyo Disneyland lineup.
 * Japan was also originally going to have a ride of some sort. Possibilities include a Mt. Fuji roller coaster (supposedly scrapped because of Fuji Film, and Kodak sponsoring other rides...seriously), and a Circlevision (similar to what Canada and China have) train ride which would've possibly been attacked by Godzilla.
 * Plans for Disney's Hollywood Studios (then Disney-MGM Studios) included some Who Framed Roger Rabbit?-themed attractions (cancelled due to legal issues), a Muppet version of The Great Movie Ride (cancelled due to Jim Henson's death) and a Dick Tracy ride (cancelled due to King Features Syndicate taking Warren Beatty to court).
 * Originally, much more of The Great Movie Ride would have been based around The Wizard of Oz—riders would be "swept away" by the tornado to Munchkinland, and the final room would be the Wizard's chamber, in which he introduced the closing Montage of great film moments. Because Ted Turner (the movie's rights-holder) stipulated that only so much time could be given over to Oz scenes, the tornado was replaced by a Fantasia segment, and the final room became nondescript.
 * There would have essentially been a Muppet-themed land had Henson not died in the early years of the park's creation. It would have been centered around the courtyard where the Muppetvision 4D theatre currently is.
 * Animal Kingdom was originally going to have a land called "Beastly Kingdom" (or perhaps "Kingdomme") based around mythical animals, but budget cuts forced that to the back burner; the space Camp Minnie-Mickey now occupies was intended for this.
 * Rumor has it that the designers of the Beastly Kingdom land jumped ship to Universal and took some of their ideas with them. Specifically, Dueling Dragons (now the Harry Potter dragon coaster) would have been a major thrill ride for Animal Kingdom.
 * What Could Have Been for Walt Disney World Hotels:
 * The Boardwalk Inn & Villas and their adjoining actual boardwalk were salvaged from plans for a mini-park that would have recreated seaside amusement parks of the early 20th century.
 * Disney's Pop Century Resort was originally going to cover 1900-1949 with a second set of buildings on the other side of Hourglass Lake, but the September 11th attacks happened shortly before the completed first set (1950–99) was to open, causing a tourism slowdown that delayed it to 2004. The second set had the building "shells" put up, but there was never enough demand for rooms to complete them; the current plan is to revamp them into Disney's Art of Animation resort.
 * WestCOT would have been Disneyland Anaheim's answer to Epcot in Florida. It would have had its own version of Spaceship Earth, a World Showcase based on the individual continents, and a Spiritual Successor to Adventure Thru Inner Space. Alas, the whole thing was scrapped in 1995, and Disney built the California Adventure park instead. (And it's too bad, because the concept art for WestCOT looked really cool.)
 * Myst almost had a Disney World attraction.
 * The Other Wiki has a whole list of attractions that Disney cancelled for whatever reason.
 * Disney announced in 2009 that they would try to compete with/catch up to Universal Studios' Wizarding World of Harry Potter by expanding Walt Disney World's Fantasyland with immersive meet-and-greets for Cinderella, Aurora, Ariel, Belle, and Tinker Bell. However, they later realized this expansion might not have an audience beyond little girls. They later decided to keep the most gender-neutral parts of the expansion, move the meet-and-greets into one of the pre-existing Fantasyland buildings, and use the newly opened space to construct a (hopefully universally-appealing) roller coaster through the Seven Dwarfs' mine.

Other

 * Graphic artist and designer Roger Dean, best known for his work on album covers and stage designs for the progressive rock band Yes, designed several theme park attractions with his brother Martyn which were never used. The sketches appear in his book Magnetic Storm.
 * Peter Pan's Neverland, a park Michael Jackson came up with the initial concept for in the late 1990s. (Scroll down the page to see the article.)