Superman was the most expensive film ever made when it was released in 1978. The movie cost $55 million to make, and it was seen as a huge risk as nobody had ever attempted to make a big-budget superhero movie before.

Luckily, the movie was a huge critical and commercial success, netting $300 million at the box office and spawning three sequels. It made stars of its its cast, including Christopher Reeve and Margot Kidder, and paved the way for superhero movies to become a genre in their own right.

Here we look behind the scenes of the movie, and catch up with some of the stars of the movie that made us believe a man could fly.

Reeve Was Nearly Turned Down Because He Was Too Skinny

It was the movie’s casting director, Lynn Stalmaster, who first suggested Reeve for the part of the movie’s title character. On seeing photos of the actor, both director Richard Donner and producers Ilya and Alexander Salkind said he looked too young and skinny to play the DC Comics hero. However, they agreed to let the actor do a screen test and were blown away with the results. Reeve was cast and piled on the pounds to fit the role, going from 170 to 212.