4. Mount Fuji Coaster (Epcot)

Inspired by the proposals to bring a version of the Matterhorn to the planned Switzerland Pavilion, Disney's Imagineers proposed the construction of a gigantic recreation of Mount Fuji at the Japan Pavilion. As with most Disney mountains, this would have hosted a roller coaster.

Located behind the pagoda that is the recognisable icon of the Japan Pavilion, the mountain would have transformed the look of one side of World Showcase's lagoon. The roller coaster itself would have raced around the outside and inside of the mountain, and would, of course, have been the first roller coaster in Epcot's line-up.

In the end, no sponsor could be found for the ride. The obvious suitor for a Mount Fuji attraction was the film manufacturer, Fujifilm. But, of course, arch-rival Kodak was already a major Disney sponsor (and sponsored the Imagination Pavilion in Epcot's Future World). It was never likely to stomach Fujifilm being featured at Epcot.

3. Industrial Revolution (Disney's America)

Championed by former CEO Michael Eisner, the Disney's America project aimed to install a historically-themed park close to Washington, D.C. This would have brought to life key elements of American history in an entertaining way - something that, predictably, many prominent historians objected to.

One area of the park was to be Enterprise, a factory town that would highlight American ingenuity. It would be headlined by the Industrial Revolution, a major roller coaster that would swoop through a 19th century heavy industry landscape complete with blast furnaces.

In the end, political opposition and concerns over profitability derailed Disney's America, and the Industrial Revolution, Disney-style never came to pass.

2. Time Racers (Epcot)

Back in the early 2000s, Disney devised a plan to completely overhaul Epcot's Future World area. At the heart of that plan sat Time Racers, a futuristic roller coaster set inside Spaceship Earth. The existing, slow-paced Omnimover dark ride that occupied the interior of the building would have been ripped out. In its place would have been a steel roller coaster reminiscent of Space Mountain: Mission 2 at Disneyland Paris. A projection system would have been employed to take riders back into recognisable scenes from history, then off into the future.

Project Gemini proved to be too expensive for Disney to pursue, with a rumored price tag of around $500 million. Had it gone ahead, Epcot could be a very different park today. Instead, Siemens took over sponsorship of Spaceship Earth, and the existing ride was given a makeover - ensuring that it will continue to whisk riders through history for some time to come.

1. Ride the Dragon (WestCOT)

Arguably the most infamous unbuilt Disney project of all time is WestCOT, the ambitious West Coast version of Epcot that was announced in 1991 for the Disneyland Resort. This would have featured its own versions of Future World and the World Showcase, surrounding an incredible icon dubbed Spacestation Earth.

The Asia Pavilion in World Showcase, shown above, would have been headlined by a steel roller coaster known as Ride the Dragon. This would have rampaged through the Dragon's Teeth Mountains, boasting cars designed to resemle Chinese-style lion-dragons. At its highest point, riders would be able to see outside the park's walls, so it was planned to have billowing red and gold silks emerge to hide the view.

In the end, the financial struggles at Disneyland Paris caused Disney to scale back its plans for the Disneyland Resort. Disney's California Adventure was built instead, on a much smaller budget - much to the regret of many both inside and outside of Disney.