Give me a brief history of the construction of Walt Disney World
Walt Disney World was designed as a theme park to supplement Disneyland.  It was conceived by Walt Disney in the 1960s and was known as the "The Florida Project".  Walt Disney originally envisioned including a planned community known as the "Experimental Prototype Community of Tomorrow" (EPCOT) which would be a planned community that would test city-living innovations.  As planning progressed, plans for EPCOT evolved to become just a theme park in the complex.  Walt Disney died in 1966 during planning and the company was torn whether to move forward with the project.  Walt Disney's brother, Roy Disney, came out of retirement to see the project successfully completed.  There are four theme parks in the complex.  The Magic Kingdom opened in 1971, followed by Epcot in 1982, Disney's Hollywood Studios in 1989, and Disney's Animal Kingdom in 1998.  Roy Disney insisted the name be changed to Walt Disney World from the original name of just Disney World to remind people that it was Walt's dream.