1. Like many other movies the eventual star wasn't the first person considered for the role. Before deciding upon the relatively unknown Christopher Reeve, Ilya and Alexander Salkind practically auditioned every young(ish) male actor in Hollywood, and then some, for the part of Clark Kent/Superman. Amongst the actors considered for the role were (deep breath...) Al Pacino, David Soul, Robert Wagner, Jeff Bridges, Steve McQueen, Christopher Walken, Robert Redford, Kris Kristofferson, Burt Reynolds, Warren Beatty, Ryan O'Neal, Jan-Michael Vincent, Jon Voight, James Caan, Nick Nolte, Robert Redford, Clint Eastwood, Nick Nolte, Dustin Hoffman, Paul Newman, Patrick Wayne, David Prowse, Arnold Schwarzenegger and Sylvester Stallone (...phew!).As well as all of them the Salkind's spoke with boxer Muhammad Ali (below), auditioned singer Neil Diamond and even screen tested Ilya Salkind's wife's dentist!2. Whilst looking for a director for their ambitious project the Salkind's spoke with both Steven Spielberg and George Lucas. Lucas was too busy with Star Wars and turned them down. Spielberg showed some interest but was busy filming Jaws. Rather than offering him a deal then and there the Salkind's passed on Spielberg, with a plan to wait and see how Jaws was received and then maybe come back to him with an offer. However Jaws was such huge successes that Spielberg skyrocketed out of price range.3. After they had both turned down the role of Clark Kent/Superman, the Salkind's offered Dustin Hoffman and Paul Newman the part of Lex Luthor. Neither wanted it, and nor did Gene Hackman initially. Even though Lex Luthor is traditionally bald in the comics, Hackman insisted he would only take the role if he didn't have to shave off his mustache or any of his hair, and also said he would not wear a bald cap on his head. To convince him to lose his mustache director Richard Donner (who was yet to meet the actor face to face) sent over a picture of himself sporting a fake bushy mustache and said he would cut off his if Hackman did the same. Hackman agreed! However Hackman stood steadfast against shaving his head, so his own natural hair was styled differently from scene to scene to give the appearance of his character having changed wigs. Hackman did finally agree to wearing a bald cap for just one day of shooting...4. When it came time to cast Superman's father Jor-El the Salkind's knew they wanted an iconic film legend to fill the role, so for the third time they approached Paul Newman and for the third time he turned down a part in the movie! Eventually a deal was done with Marlon Brando and he became a genuine record breaker. According to the Guinness Book of World Records, Brando was paid a recordin inflation-adjusted dollars) and 11.75% of the gross profits for just 13 days work playing Jor-El in Superman, further adding to his mystique.5. Brando also negotiated creative control for his character and a say in the casting of the other main roles. With no-one yet signed to play the lead part in Superman, Brando quickly set about cutting the field, dismissing Sylvester Stallone as "too Italian" and saying that no-one would be able to understand Arnold Schwarzenegger (well, he had a point). When it came to Jor-El Brando initially suggested that he played the part as "a suitcase or a green bagel", basically just providing the voice - this was after he'd been paid! Richard Donner convinced him otherwise, but only after explaining that the comic was over 40 years old and generations had grown up knowing what Jor-El looks like - and it ain't a green bagel!6. It is quite sad that Brando really did just approach Superman as a massive payday. Terence Stamp revealed in one of the special features included on the DVD release that Brando never bothered to learn any of his lines, and insisted on the use of cue cards for each of his scenes. So when he was sending his infant son off to the Earth, he was actually reading his lines off the baby's diaper.7. Once Christopher Reeve was cast he underwent a strict physical training session to put on over 40 pounds of muscle, going from 170 pounds to 212 pounds in juts a few months. The Salkind's called on the service of Darth Vader actor and professional bodybuilder David Prowse to oversee Reeve's training.8. The famous tag line for the film was "You Will Believe A Man Can Fly", and watching Christopher Reeve on the big screen zooming across the sky sure looked impressive, especially back in 1978. But figuring out how to make a man 'fly' was one of the toughest challenges the production team faced. Before settling on the wires/harness/blue screen combination various tests took place to make the flying scenes look as real as possible. The first attempt involved putting a crash test dummy in a Superman outfit inside a cannon and shooting it out skywards (for real!). After that idea was abandoned a series of hand drawn animated segments were ordered to be cut in with the live action footage, this technique had been used to make Superman 'fly' in a early serial, but unsurprisingly the finished test result looked very poor. Another test involved a small scale plaster model of Superman, which was equipped with the inner workings of a remote control helicopter - clearly that was a no-no too.9. Superman very nearly featured a musical number! When Supes takes Lois Lane on a romantic flight over Metropolis we hear her inner thoughts, wondering "Can you read my mind?". The initial idea was to have Margot Kidder perform her monologue in song. Thankfully, Richard Donner thought it was too much of a tacky idea and instead recorded a spoken voice-over featuring Kidder and an orchestra. However, the song "Can You Read My Mind? - The Love Theme From Superman" was eventually recorded by Maureen McGovern and became a minor hit in 1979...10. Superman: The Movie was originally meant to end with a cliffhanger. The nuclear missile that Superman deflects would career off into space and explode, releasing General Zod, Ursa and Non and setting up the start of Superman II. Ultimately Richard Donner decided that the ending was a little gimmicky, and felt that audiences would like the first film so much that they wouldn't need any encouragement to come back for further adventures with the Man of Steel.How right he was.