There's a Great Big Beautiful Tomorrow

"There's a Great Big Beautiful Tomorrow" is the theme song of the Carousel of Progress and Disneyland's Innoventions attraction. It was written by Robert B. and Robert M. Sherman.

History
The song was first used in the Carousel of Progress, one of several Disney attractions created for the 1964 New York World's Fair (the others being Great Moments with Mr. Lincoln, It's a Small World, and the Ford Magic Skyway), at the Fair's General Electric Pavilion. When the World's Fair closed in 1965, the show was planned to be moved to Disneyland along with the other attractions. The Carousel of Progress opened as part of the New Tomorrowland on July 2, 1967 and ran there until September 9, 1973, to make way for America Sings.

The Carousel of Progress was subsequently moved to Walt Disney World's Magic Kingdom, where it opened on January 15, 1975. However, General Electric requested that a new song be used for the show, so the Sherman Brothers wrote "The Best Time of Your Life" for this updated version of the show. General Electric ceased sponsorship of the Carousel of Progress in 1985, but "The Best Time of Your Life" was still used until 1993, at which point the show closed to be updated again for that park's New Tomorrowland. It reopened in 1994 as Walt Disney's Carousel of Progress, and an updated "There's a Great Big Beautiful Tomorrow" was again the theme song. Arrangements of "The Best Time of Your Life" and "There's a Great Big Beautiful Tomorrow" can be heard in the current background area music for Tomorrowland at Disneyland and the Magic Kingdom.

Meanwhile, at Disneyland, America Sings ended its run in 1988, after which many of the Audio-Animatronic characters were recycled into Splash Mountain, leaving the Carousel Theater empty. The theater building would lay dormant for more than ten years, when a new version of Epcot's Innoventions was installed in the building. "There's a Great Big Beautiful Tomorrow" was chosen as the theme song of Innoventions, with an instrumental version used as the area music and a lively rendition with new lyrics is sung by Tom Morrow (voiced by Nathan Lane), as a tribute to the attraction which originally occupied the Carousel Theater.