Steamboat Willie
Walt Disney's animated cartoon Steamboat Willie marked the debut of Mickey Mouse. This seven minute black and white cartoon was originally released on November 18th, 1928, and was the first of its kind to feature sound. Although Mickey did not actually speak words in Steamboat Willie, he did whistle.
Notes
This movie is referred to by the German soldier captured by Captain Miller's squad following the attack on the radar station. The end credits for Saving Private Ryan lists this German as "Steamboat Willie."