Twenty years ago today, J.K. Rowling's 'Harry Potter and the Sorcerer's Stone' was released. Initially, most thought it to be a charming children's tale about a boy who discovered he was a wizard, but Harry Potter quickly emerged from his cupboard under the stairs to take the world by storm. The series of seven books have enjoyed immense commercial and critical success, and have been translated into multiple languages. Reading Harry Potter is a rite of passage for almost any child growing up, but the franchise is equally (if not more so) beloved by adults, especially those of us who have been fans since the beginning.

Of course, we all know that Harry Potter didn't end with the books. Eight feature length movies made stars of its young cast, Daniel Radcliffe, Emma Watson, and Rupert Grint, while well known actors lined up for the chance to appear. Names include Kenneth Branagh; Julie Walters; Helena Bonham Carter; David Thewlis; David Tennant; Emma Thompson; Michael Gambon; and the late Alan Rickman, who brought Snape to life so perfectly. And the movies have only been the beginning of Harry Potter's takeover. The Harry Potter studios in the U.K., and the Wizarding World of Harry Potter in the U.S., attract hundreds of thousands of visitors each year, merchandise sales are still huge, and the stage play, Harry Potter and the Cursed Child, set 20 years after the events of Harry Potter and the Deathly Hallows, is sold out up to 18 months in advance. Not to mention, the conventions, the spoof musicals, and now, the Fantastic Beasts movie series. Harry Potter really is the franchise that never dies; it's popularity never wanes, and one little boy with a lightning shaped scar, changed Hollywood entirely.

Goyle Sr among other Death Eaters

First of all, the cinematic success of Harry Potter showed Hollywood that its source material didn't need to be aimed specifically at adults. Children have always been well catered for, with Disney, DreamWorks, Illumination Entertainment and more all vying to secure family visits to the movies. Adults, again, fare well, with a wealth of genres and ratings to choose from. Then there's the bit in between; approximately age 11-16, when you feel too old for a kids movie but you're too young to watch NC-17, R rated, or even some PG-13 rated movies. Harry Potter sat perfectly in this age range, but Hollywood also discovered that its appeal extended far beyond the target audience.

The cinematic adaptation of Harry Potter and the Sorcerer's Stone was released in 2001. This was before the MCU had come into its own, before DC had decided to start its own extended universe, and, interestingly, before all of the Harry Potter books had been published. Such was Warner Bros.' confidence in the franchise, though, that they bought the rights to the first four books from Rowling, for a reported £1 million. At the time, such a gamble on a literary franchise was unheard of, especially one that Rowling had insisted contained an all-British cast (apart from where roles deemed otherwise), and had three unknowns in the central roles - and they were children.

Harry Potter and the Deathly Hallows Part 1 Poster of Harry Ron and Hermione running through a forest.

Of course, the gamble paid off, big time. To the Hollywood execs, that suddenly opened up a whole new world of possibility; the adaptation of popular YA novels. Who can ever forget the Twilight saga? The Hunger Games also enjoyed huge success, and, like Harry Potter, both of those franchises also split their final book into two parts, in order that the detail from the story wasn't lost. Both of those franchises have had their run, they're no longer as popular; at least not to the extent that Harry Potter still is. However, not only did these three franchises prove that YA movies could draw record crowds, they also sparked the trend of planning out several movies far in advance, based on the assumption that they would all be successful.

This worked exceptionally well for Harry Potter, with fans eagerly awaiting the next book or film installment. It's also worked well for Marvel, who now build their slate years in advance, with interwoven movies connecting to larger blockbusters along the way, such as the forthcoming Avengers: Infinity War. DC have their own line-up of movies, too, but both these comic book giants tell different stories in different solo or ensemble movies, rather than giving one long, continuous franchise. The Fast and The Furious, Despicable Me, Pirates of  the Caribbean, and Transformers are just some of the most successful franchises that line up multiple movies in advance. For the most part, their faith in the ability of a franchise to keep moviegoers interested, has paid off. Though Transformers: The Last Knight has not fared too well on home shores, it has enjoyed a blockbuster opening overseas. Sometimes, however, advance planning doesn't work. Case in point; Power Rangers, which relaunched itself earlier this year with what was to be the first movie in a line of Power Rangers offerings. The movie even contained a mid-credits scene that very clearly set us up for more, but Power Rangers didn't do well at the box office either here or in China, and now it sits in a precarious position, with a sequel seeming very unlikely.

Harry Potter and the Cursed Child book sales

That said, it seems that if your story is in any way connected with Harry Potter, you're deemed a success before anyone's even seen what you have to offer. With the last movie being released in 2011, it seemed as though Harry Potter as we knew it, had come to an end. This didn't prevent the fandom from remaining hugely active, though; a spoof musical, A Very Potter Musical by Team Starkid, drew large numbers of viewers online, as did their subsequent offerings, A Very Potter Sequel, and A Very Potter Senior Year. Fans attended conventions across the globe, and continued to have a voice on Pottermore as well as social media and blogging platforms such as Tumblr. Rowling heard and paid attention to all of this, and happily engaged with her fans and continues to do so. She has written regularly for Pottermore; essays detailing finer points of the story that we may have missed, to little tidbits such as what character she regrets killing off or, most recently, explaining that Harry was named after his grandfather.

Given that the fandom wasn't dying out, Rowling went on to create the stage play, Harry Potter and the Cursed Child. Officially deemed the eighth Harry Potter story, the show mainly focuses on Harry's youngest son, Albus, and Draco's son, Scorpius. The show, which clocks in at over 4 hours of live theater, must be viewed in two parts. It received a record-breaking 11 Olivier Award nominations in 2017, and won an again record-breaking 9 of them. The show will continue in London's West End, and will also open on Broadway in 218. Unsurprisingly, Hollywood are eager to turn Cursed Child into a movie, but for as long as it continues to sell out so far in advance, such an event seems unlikely. However, it will happen at some point and, in the meantime, Warner Bros. is busy with yet another Harry Potter extension.

Fantastic Beasts and Where to Find Them was originally a short book released by Rowling to raise money for Comic Relief. It was 'written' by Newt Scamander, and came in the form of a textboook that Harry, Ron, and Hermione studied at Hogwarts. Years later, Rowling took the very notion of Fantastic Beasts, and the character of Newt Scamander, and turned it into another franchise. Again, the Fantastic Beasts movie series is planned out far in advance; what was once three films is now five, with Rowling saying it's necessary in order to tell all of the story. Warner Bros. backs her on this, and the first movie, Fantastic Beasts and Where to Find Them, was released in 2016.

The movie garnered mostly positive reviews, but that likely wouldn't have mattered anyway. A cinematic return to Rowling's Wizarding World was too good a thing to miss, and fans flocked to theaters, making it the fifth most successful entry in the Harry Potter-verse. Eddie Redmayne starred as Newt Scamander, but the franchise is set to grow far beyond a tale of one wizard who happens to like magical creatures. Fantastic Beasts introduced the dark Wizard, Grindelwald, played by Johnny Depp. Very cleverly, subsequent Fantastic Beasts movies will tell the story of his rise to power, his reign of terror across Europe, and his defeat at the hands of Dumbledore (to be played by Jude Law). The timeline of Fantastic Beasts will, in the end, tie very neatly into Harry's story, ending just before Voldemort begins his own rise to power. Rowling had all this history written long ago, before she could ever have had the notion that one day she would be writing the screenplay of what is essentially Harry Potter history. The second Fantastic Beasts movie will film this summer, for release in 2018.

Rowling is, undoubtedly, a literary genius in her own right. What no one realized, when Harry Potter first arrived on bookshelves, is that she also manages to repeatedly tap into the hearts and minds of people across the world; old, young, anywhere in between, it doesn't matter. For millions, Hogwarts will always be home.

NEXT: Guillermo del Toro Regrets Turning Down Directing Harry Potter

Key Release Dates