Good Gear Guide
The World's Fair and Technology: 8 Amazing Highlig...
Motion pictures with recorded sound may have been presented to the general public for the first time at the Paris Exposition of 1900. (Competing systems included Phono-Cinema-Theatre, Phonorama, and Theatroscope.) In any event, recorded sound didn't become a commercially viable part of the movies until the "Talkies" of the 1920s. (This also happens to be when Hollywood grew into a global force in the film industry.)
Twenty years later, Chrysler Motors gave the first commercial 3D film (requiring Polaroid glasses for viewing) to appear in the United States its premiere at the 1939 New York World's Fair.
Image credit: Wikipedia
The World's Fair and Technology: 8 Amazing Highlights