Wikipedia is a wonderful wealth of knowledge that can be utilized to both entertain and inform on almost any subject. And Disney Parks are no exception. Wikipedia has a page entitled "List of never built Disney attractions." It is a gigantic list, with details, names, and, occasionally, links, of Disney rides, lands, restaurants, etc. that were once in their planning phases but never made it to their final building stages. The list, of course, is nowhere near exhaustive since there are thousands upon thousands of projects that the public will never even know about. That doesn't mean that this list is meaningless, however, this list makes a great read and makes you wonder about the rides and attractions that could have been. It also makes you feel sorry for the hundreds of Imagineers who slaved away for countless hours on their visions to only have them tossed in the trash can. I recommend heading over to Wikipedia and reading everything from WestCOT to Dick Tracy's Crime Stoppers and Mythia to Beastly Kingdom. The above image is concept art for the never-realized Disney park Port Disney, an American version of the Tokyo DisneySea park to be located in Long Beach, California.
Source: Disney and More