It's a bird! It's a plane! It's ... a series of elaborate harness systems.

From the moment Superman: The Movie hit theaters in December 1978, it was pretty much an instant classic. The most expensive movie ever made at the time, the flick's humor, advanced special effects, and iconic cast made it a worthy MCU predecessor. 

From directorial chats to Christopher Reeve resetting between takes, here are 23 behind-the-scenes pics from 1978's Superman: The Movie.