Ode to Horizons - A True Classic of EPCOT Center

The Attraction
Horizons began with a section entitled "Looking Back at Tomorrow," showcasing visions of the future as perceived from the era of Jules Verne through the 1950s. The ride then moved past two immense OMNIMAX screens (groundbreaking technology at the time the ride was built), showing modern technologies and ideas that could be used to build the world of tomorrow. Afterward came the main part of the ride: visions of futuristic life in cities, deserts, undersea, and even in space. The only Disney attraction with multiple endings, Horizons then allowed riders to select which path they wanted to take back to the FuturePort: from the space station Brava Centauri (depicting space colonization), from the desert farm of Mesa Verde (depicting arid-zone agriculture), or from the Sea Castle research base (depicting ocean colonization).
As the final part of the ride, guests in their 'omnimover' would push a button to select amongst the three choices and would be presented with a 31-second video sequence. A film would then be displayed to riders in each individual car. The videos showed a simulated flyover of an outdoor scene. To create the effect, scale models were built and a camera swept across the futuristic terrain. The models were some of the largest ever created at the time.
The model for the desert sequence, for example, was 32 feet (9.8 m) by 75 feet (23 m) long. The visual effects were filmed in a hangar at the Burbank airport. Produced in 1983 by 30 model makers, it took over a year to build and shoot the three segments. The exit corridor of the ride originally featured the mural The Prologue and the Promise by renowned space artist Robert T. McCall.

History
Horizons, in its concept phase, was named Century 3 (or Century III), to recognize the third century of American existence (1776-2076). The name was changed to Futureprobe to help appeal the attraction toward international guests who wouldn't understand or appreciate Century 3. In the end, the Futureprobe name was scrapped due to the medical connotation of the word "probe". After much debate, GE and Disney officials settled on the name Horizons. Prior to the start of construction, the project's budget was slashed by $10 million (USD). The building size was reduced and the length of the ride was shrunk by 35%, shortening the ride length by 600 feet (180 m).
Horizons opened exactly one year after Epcot opened and was located between World of Motion and Universe of Energy. Wonders of Life became Horizons' new neighbor in 1989, and World of Motion closed in 1996. Horizons remained operational until World of Motion's successor, Test Track, was ready to open to the public in early 1999.
It was proposed that Horizons would be the sequel to the Carousel of Progress (located in Tomorrowland at Magic Kingdom), Disney's ride from the General Electric Pavilion at the 1964 New York World's Fair. As the Carousel of Progress followed the changes in lifestyle that faced a family as they lived through the 20th century, Horizons continued their story, showing how they might live in the 21st century. The Carousel's theme song "There's a Great Big Beautiful Tomorrow" was part of the Looking Back at Tomorrow portion of Horizons. The version of "There's a Great Big Beautiful Tomorrow" that could be heard in Horizons coming from a television in the Art Deco scene is the exact version that can still be heard on a radio during the first act of the Carousel of Progress today.
The original ride concept came from Reginald Jones (then CEO of GE) and Jack Welch (future CEO of GE). The concept was to focus on Thomas Edison and his body of work along with the origin of General Electric; it was changed to focus on the future of America, a theme that changed yet again to respect that Epcot was to appeal to a global audience. The building which housed Horizons was designed to resemble a spaceship, while accentuating the third dimension and giving the impression of an infinite horizon.
During the early 90s, after GE had dropped sponsorship, some ideas were tossed around about the pavilion being turned into a space-themed pavilion. The building would have been upgraded and rethemed. The ride system would be changed drastically, in which the guest would be in an individual space harness while viewing space stations and space in general and would control the pitch and yaw of the vehicle.

On January 9, 1999, Horizons was closed.

No reason was publicly given, but the lack of corporate sponsorship probably played a large part in the decision. It is also claimed that one of the reasons for the attraction closing was major structural problems (that being a large sink-hole underneath the structure which emerged in 1998), along with problems with the roof. The building was claimed to have been close to collapsing under its own weight.
The building stood unoccupied for well over a year as Disney decided between either relaunching the attraction (which would have required a new storyline and major building renovation and upgrades) or demolishing the building and creating a new attraction in its place. It was decided to build a new cutting-edge outer space-themed attraction, so the Horizons building was slowly torn down in July 2000. The demolition of the building marked the first time in Disney history that an entire ride building had to be demolished in preparation for a new attraction. Construction on Mission: SPACE began in late 2000 and the new attraction opened in 2003.
Various props from Horizons have been displayed around Walt Disney World and even in Walt Disney Studios Park at Disneyland Resort Paris. A display that features the butler robot animatronic was set up in EPCOT: Creating the World of Tomorrow for Epcot's 25th anniversary. At Disney's Hollywood Studios, a few of the props from the underwater city scene are displayed in one of the studio warehouses. And one of the Desert ships has made its way to Disney's Hollywood Studios, hanging from the ceiling of a restaurant.