One of the earliest Tomorrowland attractions at DISNEYLAND was the 20,000 Leagues Under the Sea walk through exhibit.
When the construction of Tomorrowland fell behind, Walt Disney needed some filler attractions. He quickly came up with the idea to take the props from his latest hit- 20,000 Leagues Under the Sea.
The exhibit allowed DISNEYLAND guests to do something that was a rarity at the time- see authentic sets and props from a famous movie.
The exhibit is long gone, but today's guests can still see one of the props from the movie in the park- the organ from the film, slightly modified, exists in the ballroom scene at the Haunted Mansion.