The ending of Lost could well be the most widely misunderstood series finale in television history, but it almost drew to an altogether more volcanic close.

Remember that flashback which sees Ben being taught about the island's volcano as a youngster by the Dharma Initiative? Probably not. It occurs in third season episode 'The Man Behind the Curtain' and it's now emerged it was “one of the first hints of an endgame."

Showrunners Damon Lindelof and Carlton Cuse spoke to EW about the scrapped plans last year.

The story goes that Cuse - very much the duo's big-dreamer - got the idea of including a volcano at the end of the series after visiting Hawaii's Big Island with his family, and later envisioned it being home to the climactic showdown between Jack (Matthew Fox) and the smoke monster, incarnated as John Locke (Terry O'Quinn).

“We were always looking to cannibalise anything on Hawaii to aid in the visual storytelling of the show,“ Cuse said. ”We also thought of the island as a character on the show, so we were always looking for things that would give it more personality.”

For those who don't know (and if you haven't seen Lost, go watch it immediately), season six presented the concept that the island was a metaphorical cork bottling up some very bad things that, if unleashed into civilisation, would cause all kinds of destruction.

Lindelof - whose latest series The Leftovers ended with acclaim in 2017 - added: “The question was always, how do you basically visualise and dramatise the idea that the island itself is all that separates the world from hellfire and damnation? And the answer was the volcano.”

The volcano was first mentioned in season three, episode 20

He continued: “The volcano had been dormant for the duration of the series but based on moving into this endgame, the island had become unstable and the volcano was going to erupt.

"We were going to have lots of seismic activity, and ultimately, there was going to be this big fight between the forces of good and the forces of evil, which ended up in the series manifesting as Jack and The Man in Black, in the midst of magma. Magma spewing everywhere!”

The volcano was later deemed too expensive by the bigwigs at network ABC forcing the writing duo to improvise (the fatal battle ended up happening on a cliff).

“ABC was like, ‘Guys, we love you, and we’re letting you end the show; we can’t let you bankrupt the network in the process',” said Lindelof.

Film premises that shouldn’t have worked but did Show all 14 1 /14 Film premises that shouldn’t have worked but did Film premises that shouldn’t have worked but did 1. Cloudy with a Chance of Meatballs Kicking us off is Phil Lord and Christopher Mille’s bizarre animated film about a scientist who creates a machine that transforms water into food. So far, not too crazy, but then the machine gets stuck in the sky and it starts raining food. Everything goes wrong and Flint Lockwood must save the day by flying up to the machine and kicking fried chicken butt. Yeah, a pretty crazy premise, but a fantastic film. Film premises that shouldn’t have worked but did 2. Frank Michael Fassbender may be one of the most bankable stars of the moment - having starred in the likes of Steve Jobs, X-Men and Macbeth - but in 2014, instead of flaunting his face, producers decided to make him wear a weird papier-mâché mask for the film’s near entirety. The plot see’s Fassbender’s titular character front a rock band, play SXSW and make ‘likeable’ music. It’s all just a bit strange. Film premises that shouldn’t have worked but did 3. Groundhog Day Almost anything with Bill Murray in it is a win in my book, but when you say the premise of Ground Hog day out loud - a weatherman who must relive the same day over and over again - it sounds quite boring. What transpired was one of Murray’s funniest films. Film premises that shouldn’t have worked but did 4. Star Wars With Star Wars being so prevalent in pop-culture, it’s hard to imagine a time when no-one except George Lucas knew what a Lightsaber was. Producers must have been shocked when this young director came into the office trying to sell a script about Luke Skywalker, R2D2, Darth Vader, Chewbacca and Stormtroopers. Thankfully, they believed in his vision and now we have one of the best sci-fi sagas of all time. Film premises that shouldn’t have worked but did 5. Incepetion A dream, within a dream, within a dream. Even those who watched Inception were left confused, let alone those who only heard what the film was about. Christopher Nolan’s final flick, however, was a masterclass in storytelling and one of the best films of the last ten years. Film premises that shouldn’t have worked but did 6. Speed The high-concept Speed is quite ridiculous really. Keanu Reeves can’t let a bus go below 50 miles per hour or it will blow up. It’s quite amazing how Jan de Bont managed to make his debut 116 minutes long in the first place, let alone making it a decent film in the process. Film premises that shouldn’t have worked but did 7. Edward Scissorhands Tim Burton is a director who could fill this entire list up. While he may have chosen to reboot numerous films in the past few years (Alice in Wonderland, Charlie and the Chocolate Factory, the upcoming Dumbo 2) it was his original concepts that set him apart from everyone else. In Burton’s head, the love story of a man with scissors for hands and a young woman made complete sense, while for everyone else - from just the premise - it seemed entirely weird. Luckily, he was given the opportunity to make the film and a cult classic was born, all while Johnny Depp’s ability to play the outsider was solidified. Film premises that shouldn’t have worked but did 8. Mrs Doubtfire Post-Hook and Aladdin, Robin Williams was on a role. One of his standout performances was as Mrs. Doubtfire, the father-turned-drag-housekeeper. As a premise, dressing your lead male as a woman wasn’t exactly new (see Dustin Hoffman in Tootsie), so the filmmakers ran the risk of it all seeming like an overdone joke. Luckily, Chris Columbus managed to pull off the ridiculous plot (how wouldn’t the kids know it’s their father, really?) leading to one of the funniest films of the 90s. Film premises that shouldn’t have worked but did 9. The Lobster Like Burton, most of Yorgos Lanthimos’s films could probably feature on this page, but we’ve gone with The Lobster. The film tells of a hotel where residents must find a suitable partner within 45 days otherwise they will be turned into an animal. Try to run away and the other residents will hunt you down with tranquillisers. The result was one of the best love stories of 2015. Film premises that shouldn’t have worked but did 10. Ant-Man Some comic book superheroes should not be adapted to the big screen (*cough* Howard the Duck *cough*). Ant-Man is not one of them. Against all the odds, Paul Rudd and Peyton Reed managed to make a compelling film about a man who could shrink down in size and control ants. What’s incredible is that - somehow - the film quickly became one of Marvel’s most beloved films. Of course, everyone knew Marvel could pull off weird, having knocked it out of the park with Guardians of the Galaxy the year before. Film premises that shouldn’t have worked but did 11. Beetlejuice Two ghosts living in their old home want to scare away the alive people who now live there. Unfortunately, the new home-owners can’t see them and so the ghosts have to call upon a deranged Michael Keaton to help them out. Add one of the strangest afterlife scenes in film history and you’ve got a brilliant film. Film premises that shouldn’t have worked but did 12. Forrest Gump While not an obvious contender like Star Wars or Beetlejuice, when you think about it, Forrest Gump is a weird idea. A below-average intelligent man, sitting on a bench, waiting for a bus, telling strangers about all the famous moments in history where he observed/effected. Thanks to Tom Hanks, Gump was a magical film of love and hope, winning over the hearts of thousands and becoming an instant classic. Film premises that shouldn’t have worked but did 13. The Lego Movie Another film from Phil Lord and Christopher Miller, The Lego Movie shouldn’t have worked. Making a beloved toy into a film; it was all just a bit silly. Thankfully, Chris Pratt’s turn as Emmett (and a catchy song in “Everything is Awesome”) the film was a huge hit with critics and fans alike, and now we have a cinematic universe of Lego movies to come. Awesome? Film premises that shouldn’t have worked but did 14. I’m Not There “Let’s get Christian Bale, Cate Blanchett, Marcus Carl Franklin, Richard Gere, Heath Ledger, and Ben Whishaw to all play Bob Dylan in a single film”, Todd Haynes said. While you would think that would be overkill, the result was stunning, with Dylan himself eventually praising the film in 2012.

And in case you're one of the people who misunderstood the ending, allow us to spell it out for you: they were not dead the entire time (as The Telegraph explains here).

Emmy award-winning series Lost originally aired in 2004 and drew to a natural close in 2010. Its ensemble cast included Evangeline Lilly, Michael Emerson, Elizabeth Mitchell and Josh Holloway.