I always knew about the advent of sound in films due to the movie Singin' in the Rain. What I did not know was today's fact. On this date in 1926, Western Electric and Warner Brothers developed Vitaphone (pictured above), a new way to add sound to film.
As early as 1919 and 1920, Lee De Forest tried to develop ways of adding sound to film, but audio fidelity was not too good. In addition to this, movie studios were just not overly interested. Vitaphone was a process where sound was recorded on a disk, and then the sound was synched with the movie. Don Juan was the first film to use this technique. There was no dialogue yet--just music and sound effects. The first "talkie" picture happened the following year with The Jazz Singer.
I don't think today we take movie sound for granted. We can't imagine a world where pictures did not have sound. It's actually amazing to realize that the advent of sound in pictures is not even a hundred years old yet. How far we have come in such a relatively short period of time.