Production Design
The Godfather was shot on 35 mm film—kickin' it old-school (because it really was old school and digital film hadn't been invented yet). Additionally, it was filmed on location in New York City and Sicily, although Coppola had to fight for this to happen. The producers initially wanted to shoot it in Kansas City or on their own studio's lot.
One cool fact about the film is that the cinematographer, Gordon Willis, insisted on shooting every scene from angles mimicking a first-person, human perspective. There's just one major deviation from this: Coppola convinced Willis to shoot part of the scene where Don Corleone is almost assassinated from an aerial angle, telling him that this represented God's perspective on the event.
Coppola also used groundbreaking lighting in the movie, insisting on using shadows and darkness to create effect. His more painterly attitude toward the mixture of light and shadow became very influential.