09/30/2011 07:45 am ET | Updated Nov 30, 2011

Disney World 40th Anniversary: Share Your WDW Memories (VIDEO)

Work on the "Florida Project," as Disney World was called in its early stages, began in a swampy Central Florida after Walt Disney's death in 1966. Three weeks prior to the official opening, 100,000 Central Florida locals participated in trial runs. Come October 1, 22 park attractions were ready to go and 5,000 cast members were in costume to greet guests.

“Here in Florida, we have something special we never enjoyed at Disneyland... the blessing of size,” Walt Disney once said. “There’s enough land here to hold all the ideas and plans we can possibly imagine.”

Roy Disney echoed his brother on October 1, 1971, as the Magic Kingdom's turnstiles clicked for the first time, referring to Walt Disney World as "this happy place," a phrase Walt had deployed during the opening of Disneyland in 1955.

Embracing that sentiment, Walt Disney World grew to encompass EPCOT (previously EPCOT Center) in 1982, Disney's Hollywood Studios (previously Disney-MGM Studios) in 1989, and Disney's Animal Kingdom in 1998. Add to that a massive shopping, dining and entertainment complex, golf courses, two waterparks and a slew of resort hotels, and you've just begun to scratch the surface. And, as the park complex reaches its ruby anniversary, even more changes are afoot. A Fantasyland expansion will soon be open, plans for an Avatar-themed land are in the works and the new Art of Animation Resort will open in 2012.

To think: It all started with a mouse.

Brush up on your Disney nostalgia with the slideshow below, and share your favorite WDW memory with us.

Disney Nostalgia