5. Oceana

The most ambitious element of the proposed DisneySea theme park in Long Beach was Oceana, a stunning, multi-domed structure that would have been the world's largest aquarium. This would have featured tidal exchange with actual ocean, so as the tide changed, the levels of water in the outside display tanks would rise and fall.

The aquarium would have held a ridiculous 10 to 12 milliongallons of water, making it double the size of the one at Epcot's Living Seas pavilion (itself the world's largest when it opened). Oceana would also have hosted a real, working research center, bringing together scientists from around the world. Unfortunately, the disastrous opening of Disneyland Paris and alternative plans for a new park next door to Disneyland meant that Oceana was never built, even as part of Tokyo DisneySea (which borrowed some concepts from the California proposals).

4. Dick Tracy's Crimestoppers

Disney has produced several interactive rides, most of them based on the Toy Story franchise. The likes of Buzz Lightyear's Space Ranger Spin and Toy Story Midway Mania see guests blasting away at relatively innocent targets such as Zurg's toy minions, balloons and smashable plates.

The laser gun technology employed by the Buzz Lightyear ride could have been put to a very different use had a plan to base an attraction on Warren Beatty's 1990 movie Dick Tracy gone ahead. This would have seen guests shooting at audio-animatronic HUMAN adversaries, as they raced through the streets of Chicago blasting bad-guys. In the end, Dick Tracywas not quite the success that Disney had anticipated. Plans to install the ride at Disney-MGM Studios and Disneyland were dropped, along with plans to bring a version of the ride to Disney-MGM Studios Europe, a second park that was originally planned for the EuroDisney resort.

3. WestCOT's World Cruise

WestCOT was conceived as a West Coast version of EPCOT Center in the late 1980s, and was to be the second theme park at the Disneyland Resort. Unlike EPCOT Center's World Showcase, WestCOT's version would not have featured pavilions inspired by individual countries. Instead, they were to be themed around regions, and would have hosted both rides and restaurants. Passing through all of the pavilions would have been an enormous boat ride, the World Cruise. This would have featured five stops, with animated scenes between each station. Emerging in the exterior waterways of each pavilion, the ride would have had an incredible running time of some 45 minutes. When the EuroDisney resort descended into financial disaster, Disney reigned back its plans in Southern California. WestCOT was never built, with Disney California Adventure eventually being constructed in its place.

2. The Island at the Top of the World

Designed by legendary Imagineer Tony Baxter for Disneyland in 1970s, Discovery Bay would have taken over a large section of Frontierland. The area would have been themed around a San Francisco-style harbor, but with fantasy elements such as the Nautilus submarine from 20,000 Leagues Under the Sea and the Hyperion airship from The Island at the Top of the World. As many as three attractions would be housed in the Nautilus, including a walkthrough, a "undersea" restaurant and a simulator ride. Elsewhere, a roller coaster would wind around a Tesla Coil, and a Chinatown area would host fast food outlets and a shooting gallery. The headliner, though, was a "balloon ascent" attraction themed around The Island at the Top of the World. It would have been quite a spectacle. But when the movie bombed at the box office, The Island at the Top of the World ride - along with the rest of Discovery Bay - was parked for good.

1. Fire Mountain

Back in the late 1990s and early 2000s, Disney's Imagineers worked on many concepts to ease guests' disappointment about the shuttering of 20,000 Leagues Under the Sea: Submarine Voyage at the Magic Kingdom. One of these was Fire Mountain, which was to headline a new sub-land in Adventureland to be known as Volcania. It was to be a roller coaster based around a mock mountain - hardly an original concept for Disney. However, the actual ride system was to be truly revolutionary. Riders would start in a traditional steel coaster, sitting in a car with the track beneath them. Suddenly, halfway through, the ride would transform into a "flying" coaster, with the track above the rider's heads and "lava" burning beneath their feet. By the time they reached the end of the attraction, the track would have switched once again, so that waiting riders would have no idea what to expect. Ultimately, the costs of achieving this trick were deemed to be too high, and Fire Mountain was reimagined as a simple flying coaster. But it never got the green light, with Walt Disney World's management focusing on revitalising Fantasyland instead.