Back to the Future is a classic film that everyone loves. But how many of these behind the scenes facts did you know about this iconic movie? Find out amazing behind the scenes details with these 15 fun Back to the Future facts, including what inspired the film, which parts of the franchise came true, and the very odd title it was originally going to have! And for more fun film facts, how about checking these out? We've got these festive Home Alone facts for Kevin McAllister fans, 16 Dumbledore facts for hardcore Potter heads, and these amazing Hunger Games facts for sci fi fans!

1. It Was First Thought of in 1980

Although the film came out in 1985, it was in the works for a while first - Bob Gale and Robert Zemeckis had been planning it for at least 5 years before it finally came to be. They knew they wanted to do a film about time travel, but they weren't sure exactly what! Luckily, Bob Gale got some inspiration when he went back to his parents house, as you'll soon find out!

2. Marty McFly Nearly Wasn't Marty McFly

Michael J Fox is iconic as Marty McFly, the hapless teen who ends up getting involved in Doc's plans to time travel. But did you know that he wasn't actually originally cast to don that orange body warmer? Even though the film makers wanted Fox, he was busy working on a sitcom called Family Ties. Originally, an actor named Eric Stoltz was cast as Marty, and several weeks were spent filming his role. But eventually, tensions with the cast and Stultz's overly serious acting meant he was recast, and the film got Michael J Fox after all!

3. Bob Gale Got the Idea When He Went Home

While Bob Gale was trying to come up with a time travel film, he happened to be visiting his parents house and came across his dad's old high school year book. Looking through it made Gale wonder if he and his dad would have been friends as teens, and, if he could time travel, what would happen if they met. And that's what gave him the idea for Back to the Future!

4. The Title Was Going to be A Bit Different

Back to the Future is a title nearly as iconic as the movie itself, but did you know it wasn't always going to be called that? Yup, the studio wanted to call it...Space Man From Pluto, a title that sounds weird and fun, but has absolutely nothing to do with the plot of Back to the Future! Luckily producer Steven Spielberg stepped in and made sure the title stuck.

5. DeLorean Sales Shot Up After the Film

The DeLorean, with its roof opening doors, might well be one of the most famous cars in the world, and it's forever associated with Back to the Future as Doc's time machine. But when they decided to use the DeLorean in the film, the car company wasn't doing so good. Putting the car in the film gave the car a whole new lease of life, and the creator even wrote a letter to the film makers saying thank you! And weirdest of all, the car was never originally going to be the time machine! In early drafts the time machine was...an old fridge!

6. There Are Two Sequels

Back to the Future wouldn't be half as popular if it wasn't the start of a three part series - with Back to the Future II being set in the future (our past, now!) and Back to the Future III set in the Wild West of the 19th century! Some people even remember the sequels better than the original, with the gadgets from the second film becoming famous in their own right!

7. Elijah Wood is in the Second Film

Yup, Back to the Future II was little Elijah Wood's first film role! He plays a boy in a diner in the future who Marty impresses with his arcade game skills! Can you spot him?

8. The Sequel Features Some Cool Tech

It might seem hard to believe now, but in the 80's, the technology from Back to the Future II looked really cool! Not only did the film feature a DeLorean time machine, it also had hoverboards, scene screens and robot waiters! It also had mini fax machines, which we're sure seemed cool at the time.

9. And Some of it is Now Real

Weirdest of all, a lot of the tech you see in Back to the Future II is actually real now! We now have real hoverboards (although they're a bit different from the film), voice activated technology, video phones and card readers! No mini fax machines though!

10. Some Elements of the Film Were Originally a Bit Different

Not only was the Delorean originally going to be a fridge, there was a whole bunch of other stuff that changed before the filming of Back to the Future. Originally, Doc Brown was going to have a pet chimpanzee (We're not really sure why), and the iconic clock tower was nowhere to be seen! And let's not even mention that title! Can you picture a film called Space Man From Pluto featuring a fridge and a chimpanzee being a classic? No, us neither!

11. It Went Through 40 Rejections

Making a movie is much tougher than it looks, and even some of the most successful films ever had a hard time getting off the ground. Back to the Future is now exception - the script was rejected 40 TIMES before eventually being greenlit (that's Hollywood speak for 'given the go ahead'). For some reason, 40 different studios and companies didn't think the film would work and said no to making it. Luckily, they turned out to be very wrong!

12. Michael J Fox Was Very Tired When Filming

Once Michael J Fox was signed on to the project, he was finally free to make the character of Marty McFly come to life. There was just one problem...he was still working on Family Ties! That meant that he was working two jobs at once, basically, and as a result, he was REALLY tired! Film crew members remember having to carry Fox to bed at the end of a shooting day, and Fox messing up lines and scenes because he was so shattered!

13. Tom Wilson Carries a Special Card

Tom Wilson is best known for playing the bully in Back to the Future. But it looks like he's a little bit too well known for his own liking. Wilson has been asked the same questions about the film so many times that he now carries cards around with him he can hand to fans so he won't have to answer them again! That's a pretty neat solution.

14. It's Become a Classic

Back to the Future is one of the most popular films ever made. It was the highest grossing film of 1985, its been seen by millions of people (and there are millions more who know all about it even if they haven't seen it) and it's also recently become a musical!

15. Hill Valley Was a Huge Set

Marty's town of Hill Valley may look like a typical American town, but the whole thing was actually a film set! The famous town square, including its clock tower, was all built specially for films, although not Back to the Future! It's called Courthouse square, and its a backlot at Universal Studios. It was originally built in 1948, and has been featured in films including To Kill a Mockingbird, Gremlins and Goosebumps 2! Have you spotted it in any other movies?

16. We've Already Been Back to the Future

Although the sequel was set in the future, since it was film in 1989, the future has now become the past! The original date Marty travels to in Back to the Future II is October 21st, 2015! It probably seemed like a long time in the future in the 80s! Since then, October 21st has become known as 'Back to the Future Day'!

17. There Was A Back to the Future Cartoon

You may be familiar with the Back to the Future movies, but did you know there was also a cartoon? Yup, after the film came out, a cartoon series followed it 1991. It focused more on Doc Brown and his family, and ran for two series!

18. The Sequels Were Filmed at the Same Time

It's pretty common now to film a movie series back to back, such as Harry Potter, Star Wars and Lord of the Rings, but back in the 80s, it was much rarer to film two movies at once! The Back to the Future sequels were filmed like this, as a way to save money and also because, originally, they were just meant to be one film! Eventually they became too big for one movie, and became the trilogy we know and love! That sounds like a lot of work!

19. There Might Be Another One Coming

There have been rumours for years about a 4th film, but it doesn't seem like anything is happening for certain...Bob Gale and Robert Zemeckis want to make sure any future projects get their final say, so if a film did come out, it would be fully in line with the originals. Watch this space!