Alan Rickman was hand-picked to play Snape by J.K. Rowling, and received special instruction from her as to his character. Rowling even provided the actor with vital details of Snape's back-story, not revealed until the final novel.

The child actors would do their actual schoolwork in the movie, to make the school setting more real.

Warner Bros. originally considered making the entire "Harry Potter" series as a set of computer animated films, or attempting to combine several of the novels into a single movie. The studio's reasoning mainly had to do with concern over the rapid aging of child actors if production ran too long on any of the films, or if production was delayed between sequels, the leading actors might have to be recast. Author J.K. Rowling vetoed both the ideas of combining books and an animated film, so the studio decided instead to produce all seven (later eight) films back to back so the same actors could play their roles in every film.

The Restricted Section scene was filmed in the Duke Humfrey's building at the Bodleian Library in Oxford. They have very strict rules about not bringing flames into the library. The makers of Harry Potter were the first ever to be allowed to break this rule in hundreds of years.

The filmmakers originally wanted to use Canterbury Cathedral as a filming location for some of the Hogwarts scenes, but the Dean of Canterbury refused to allow it, saying that it was unfitting for a Christian church to be used to promote pagan imagery. Gloucester Cathedral agreed to take its place; the Dean of Gloucester, the Very Reverend Nicholas Bury, admitted to being a fan of the books. Nonetheless, there was a huge media outcry in Gloucester when it was decided to use the local Cathedral as a filming location. Protesters wrote letters by the sack-load to local newspapers, claiming it was blasphemy, and promising to block the film-crew's access. In the end, only one protester turned up.

The inscription around the Mirror of Erised says: "Erised stra ehru oyt ube cafru oyt on wohsi". Reading the inscription backwards it says, "I show not your face but your heart's desire."

The filmmakers attempted to go the extra mile of matching the kid's appearances to how the novel describes them, by fitting Daniel Radcliffe (Harry Potter) with green-colored contact lenses, and similarly make Emma Watson (Hermione Granger) wear fake buck teeth. But when Dan's eyes reacted strongly to the contacts, and Emma couldn't talk clearly with the fake teeth in her mouth, these ideas were dropped.

Tom Felton did not read any of the Harry Potter books before auditioning, and at the audition, Chris Columbus was asking each contender for the role of Malfoy, what his favorite part in the book was. When it was his turn, Felton said his favorite part in the book was the part at Gringrotts, which is what the previous contender had just said. Chris saw through this very quickly, and thought it was very funny.

Platform 9 3/4 was filmed at King's Cross, but on platforms 4 and 5. J.K. Rowling has admitted that she mixed up the layout of London's King's Cross railway station when she assigned the Hogwarts Express to platform 9 3/4, reached by using magic between platforms 9 and 10. She meant the location to be in the inter-city part of the station, but 9 and 10 are actually among the rather less grand suburban platforms. The movie conformed to the book: the platforms seen as 9 and 10 are in real life inter-city platforms 4 and 5. However, there is, in fact a "Platform 9 3/4" at King's Cross. It's located in the walkway area between the real platforms 9 and 10, as a treat for fans of Harry Potter.

Director Chris Columbus has stated in interviews, that he was disappointed with the visual effects in this film, saying that they were "rushed" and "never up to anyone's standards," and sought to improve them for Harry Potter and the Chamber of Secrets (2002). This did not, however, prevent the film from being nominated for a BAFTA award for "Best Visual Effects."

The Hogwarts motto, "Draco dormiens nunquam titillandus", means "never tickle a sleeping dragon".

Richard Harris had trouble remembering his lines, and Daniel Radcliffe would ask him to help with running his lines, just to give Richard more practice.

In order to make the Dursleys' house even more unpleasant, set decorator Stephenie McMillan deliberately sought out the ugliest furnishings possible.

In the film, the scar on Harry's forehead is off-center. This was done at J.K. Rowling's request. Due to the artwork on the covers of her books, many people have assumed that his scar is supposed to be in the center of his forehead. The books, however, never specify exactly where on his forehead the scar is located.

West Anglia Great Northern Trains, the company that owns "Platform 9-3/4", affixed one-quarter of a luggage trolley forwardly "disappearing" into the wall so as to allow fans (and their parents) to take pictures of themselves seeming to disappear into the wall.

Rosie O'Donnell and Robin Williams were two of the celebrities who had asked for a role in the movie without pay, in their cases, Hagrid and Molly Weasley. They didn't get these roles, because J.K. Rowling wanted a strictly British/Irish cast.

J.K. Rowling revealed on her website that she was considered to play Lily Potter during the Mirror of Erised scene, but she turned down the role, which instead went to Geraldine Somerville.

Robbie Coltrane was the first person to be cast.

In the script, the flashbacks to Voldemort killing Harry's parents were written by J.K. Rowling herself. The producers knew she was the only one who knew exactly what happened.

At the time this film was in production, only four of the eventual seven books in the series had been published. J.K. Rowling was retained as a consultant on the film, not only to ensure consistency with the first book, but also to avoid conflicts with her vision for the later entries. It has been confirmed that at least one line of dialogue was removed from the script to avoid a contradiction with the then-unpublished "Harry Potter and the Order of the Phoenix".

The scenes at Hagrid's Hut were filmed on location, albeit in a small patch of land in London, not far from Leavesden Studios. The hut was demolished, when the shoot wrapped, in case fans of the film swamped it.

The last name "Dumbledore" means "Bumblebee" in Old English. Also, according to the factoid trivia show QI (2003), the word "Muggle" existed in the early to mid-1900s, as a "jazz-word" that was used for pot smokers.

In order to give Hogwarts Castle an authentic look and feel, much of the filming was done at locations around England, including Christ Church, Oxford, Durham Cathedral, Gloucester Cathedral, and Alnwick Castle. In fact, the only sets that were built for Hogwarts were the Great Hall, the Grand Staircase, and the Gryffindor Common Room. In the later films, additional sets would be built for the various classrooms and other locations around Hogwarts.

Nicolas Flamel, mentioned as the creator of the Philosopher's/Sorcerer's Stone, has figured as a plot device in novels, featuring characters such as, Batman, Indiana Jones, and Robert Langdon of The Da Vinci Code (2006). He was (possibly) a real alchemist (born in France around 1330) who was believed by some people to have produced the Philosopher's Stone. Since there were mysterious circumstances surrounding his death in 1418, it has been rumored that he lived for hundreds of years. The book/movie gets his age right.

The movie, as well as the novel, are known as "Harry Potter and the Philosopher's Stone" everywhere except the U.S., and so, every scene in which the Philosopher's Stone was mentioned, was filmed twice (once with the actors saying "Philosopher's", and once with the actors saying "Sorcerer's"), or redubbed (notably, one of the times Hermoine says it in the library, her face isn't shown). The reason for this, was to keep the film consistent with the book: the U.S. publisher, Scholastic, had changed the title (and corresponding text) to "Sorcerer's Stone". The title change was done with the consent of J.K. Rowling, but she has since said, that she regrets having granting permission, and as a fledgling author, she wasn't in a strong enough position to fight it at the time.

When holding auditions for the role of Hermione, the casting team traveled around to local British primary schools to hold auditions in the hopes to find their actress. When they arrived at Emma Watson's school, she had no desire to audition, despite nearly every girl in her school wanting to. It was encouragement from her teacher, to at least attempt the audition, that made her the last girl to audition of her school.

The floating candles in the Great Hall were created using candle-shaped holders containing oil and burning wicks and suspended from wires that moved up and down on a special effects rig to create the impression that they were floating. Eventually one of the wires snapped due to the heat of the flame causing the candle to fall to the floor. Fortunately, no one was injured, but the decision was made to re-create the candles using CGI for the following films as using real candles was determined to be a safety hazard.

During filming, Daniel Radcliffe changed the screen on Robbie Coltrane's mobile phone to Turkish. Coltrane had to phone hair designer Eithne Fennel's Turkish father in order to find out Turkish for "Change Language".

The film reveals that the twelfth use for dragon's blood is an oven cleaner.

Three owls play Hedwig: Gizmo, Ook, and Sprout, but mainly Gizmo.

Hagrid is eight feet six inches tall.

J.K. Rowling insisted that the principal cast be British, and she got her wish, with two main exceptions - Richard Harris was, of course, Irish, and Zoë Wanamaker, though she has made her name as a "British" actress, was actually born in the United States. Other non-Brits in the cast include Verne Troyer, born in Michigan, plays Griphook, but he's dubbed by a Brit; and Chris Columbus' daughter, Eleanor Columbus, who played Susan Bones, though she never says a word. It's also been noted that Emma Watson was born in France, to British parents.

The tabby cat, used in the movie, ran away during filming, and came back two days later.

Richard Harris only agreed to taking the part of Albus Dumbledore after his eleven-year-old granddaughter threatened never to speak to him again. Patrick McGoohan was originally offered the role, but had turned it down due to health reasons. Ironically, Harris had health issues of his own, dying of Hodgkin's lymphoma shortly before the release of Harry Potter and the Chamber of Secrets (2002).

The platform attendant at King's Cross who asks Harry, "You think you're funny, do you?" actually works for GNER. He is, however, a train manager and not a platform attendant.

Throughout the Harry Potter franchise, Daniel Radcliffe went through 160 pairs of glasses.

The floor in the great hall is made of York stone. Production designer Stuart Craig had the foresight to invest a significant amount of his design budget on the stone. While this decision was questioned at the time, it proved to be a wise one, as the stone was durable enough to withstand the footsteps of hundreds of actors, as well as several camera crews, over the next decade to film the entire series.

By February 2002, this was the second highest grossing film worldwide after Titanic (1997).

In this film, all the food that you see in the Great Hall feasts are real. Chris Columbus wanted a very elaborate welcome feast to match the description in the book, with roast beef, ham, turkey, and all the trimmings. Unfortunately, filming under the hot stage lighting, for hours at a time, quickly caused the food to develop an unpleasant odor, despite the meat being changed every two days and the vegetables twice a day. For the following films, samples of real food were frozen, so that molds could be made of them, and copies cast in resin.

Neville receives a remembrall from his grandmother, but he doesn't remember what he has forgotten. In that scene, Neville is the only student without his robe on. He must have not remembered to put his robe on.

In the trophy cupboard, to the right of the Quidditch trophy, you can see the "Service to the School" trophy with part of "Tom M. Riddle" engraved on it; the trophy and the name on it are confirmed by Ron in a deleted scene from Harry Potter and the Chamber of Secrets (2002).

The Wizard's chess set, that Harry and Ron were playing with in the Great Hall, is based on the Lewis Chessmen, which date from the 12th Century. They were found in 1831, on a beach on the Isle of Lewis, Outer Hebrides, Scotland. In all, 93 pieces were recovered, with 11 now residing at the National Museum of Scotland in Edinburgh and 82 at the British Museum in London.

The trouble-making poltergeist Peeves (played by Rik Mayall) does not, in the end, appear in the movie, nor in deleted scenes on any home editions of the film. Mayall claimed he didn't find out that he was cut from the film, until he saw the movie himself. Ultimately, Peeves was never used in any of the Harry Potter films. Mayall claimed that he was cut because the young actors kept corpsing at his performance.

On the Quidditch trophy that has Harry's father's name on it, there are additional inscriptions for M. McGonagall and R.J.H. King. The latter being a reference to John King, the supervising art director on the film.

Liam Aiken was originally given the role of Harry, but a day later the offer was revoked, when it was discovered that he wasn't British (Aiken had previously worked with Chris Columbus).

Julie Walters has said that had she known that fellow Midlander Mark Williams would be cast as Molly Weasley's husband Arthur in the following film, she would have played up their shared accent, feeling this would have helped signpost their family's perceived uniqueness in the magical world.

In addition to Steven Spielberg, other candidates for the director's chair were Jonathan Demme, Terry Gilliam, Mike Newell, Alan Parker, Wolfgang Petersen, Rob Reiner, Ivan Reitman, Tim Robbins, Brad Silberling, M. Night Shyamalan, and Peter Weir. Newell would later direct the fourth entry of the series, Harry Potter and the Goblet of Fire (2005). Gilliam was J.K. Rowling's first choice, but the studio finally picked Chris Columbus to direct, because he had experience directing child actors. Columbus was also asked many times by his daughter to direct, and he agreed after he read her copy of the book.

Rik Mayall only took the part of Peeves as the children at his own kid's school were talking about the books. He later said, "The film, with respect ... no, with no respect at all... the film was shit".

Robbie Coltrane's 6'10" body double for Hagrid is former England rugby international, Martin Bayfield.

James Phelps and Oliver Phelps, the twin actors who play Fred and George Weasley respectively, both have naturally dark brown hair which was dyed red for their roles. Similarly, Tom Felton's hair, which is also naturally brown, was bleached blond for his role of Draco Malfoy.

In the second book of the series, "Nearly Headless" Nick invites Harry to his "deathday" party, celebrating the 500th anniversary of his demise in 1492 (a fact that fans have used to place the entire book chronology in the years 1991-1997). 1492, is, of course, the year that Christopher Columbus made his famous voyage to the New World; this film's production company is "1492 Pictures", a deliberate reference to Chris Columbus' famous namesake.

At one point, when Harry, Ron, and Hermione are approaching Hagrid, he can be seen playing a wind instrument. He is playing Hedwig's Theme.

Warwick Davis, who played Professor Flitwick and the first Gringotts Goblin, also provided the voice for Griphook, who was physically played by Verne Troyer.

The statue of the humpbacked witch, in the corridor leading to Fluffy's chamber, is a secret entrance leading to Honeydukes.

David Thewlis, who later played Professor Lupin in Harry Potter and the Prisoner of Azkaban (2004), was considered for the role of Professor Quirrell.

Daniel Radcliffe learned he'd won the role of Harry Potter while in the bathtub.

J.K. Rowling hand-picked Robbie Coltrane, Maggie Smith, and Alan Rickman for their roles.

Harry Potter's birthday is stated in the books to be July 31, 1980, as J.K. Rowling was born on July 31, 1965. By coincidence, actor Richard Griffiths (Uncle Vernon) was born on July 31, 1947. Daniel Radcliffe was once reported to been born on July 31, 1989, but this was merely a publicity stunt. In fact, Radcliffe was born on July 23, 1989.

Professor Quirrell's classroom was filmed on location at Lacock Abbey in Wiltshire, in a room known as the Warming room. The cauldron seen in the room is not a prop, but in fact came with the location. It is believed that the cauldron is over 500 years-old, and was used by cooks who worked for Queen Elizabeth I.

Ron's choice of opening, in the final chess match, is called Center Counter Opening (or Scandinavian Defense), which, due to its asymmetrical nature, is said to be a highly unpredictable, and difficult opening for either side, that rarely results in a draw.

When Chris Columbus was asked what type of child he wanted to play Harry Potter, he used a clip of Daniel Radcliffe from David Copperfield (1999) to show them what he wanted.

The only Harry Potter film not to feature Mark Williams, who plays Arthur Weasley.

As his audition, Rupert Grint sent a video of himself rapping while explaining why he wanted the part of Ron.

The exterior used for King's Cross Station, is actually St. Pancras Station, which is just down the road. This was used because the façade of St. Pancras is more visually appealing than that of King's Cross.

Almost all the scenes with Harry and/or the trio were filmed in chronological order, most notable exceptions being: The final scene in the film, where the trio return home on the Hogwarts Express, was the first scene filmed, followed by the scene when Harry first sees the locomotive at Platform 9 & 3/4 (the only other scene which required the actual train present). Then, the Quidditch match was the last thing filmed, mostly due to how long it took the effects departments to figure out how to do it.

When filming the scenes at Gloucester Cathedral, the cathedral's modern electric signs, light switches, and door locks had to be concealed behind panels that were painted to match the rest of the stone walls. The stained glass windows were also modified to hide the fact that the building was a church; the religious symbols were covered with colored plastic filter paper to blend in with the surrounding glass. One window depicted the naked figures of Adam and Eve; they were given clothes and even the trademark Harry Potter lightning scars on their foreheads.

Chris Columbus had wanted Daniel Radcliffe for the lead role since he saw him in David Copperfield (1999), before the open casting sessions had taken place, but had been told by Susie Figgis that Radcliffe's protective parents would not allow their son to take the part. Columbus explained that his persistence in giving Radcliffe the role was responsible for Figgis' resignation. Radcliffe was asked to audition in 2000, when David Heyman and Steve Kloves met him and his parents at a production of Stones in His Pockets in London. Heyman and Columbus successfully managed to convince Radcliffe's parents that their son would be protected from media intrusion, and they agreed to let him play Harry.

Chris Columbus was amazed how beautifully Daniel Radcliffe, Emma Watson, and Rupert Grint matured over the Harry Potter franchise, both physically, and as actors, compared to some child actors who start out adorable, and either lose that, or become bad actors as they grow older.

The word 'bloody' appears in the film six times, along with one 'arse', one 'bugger', and two 'blasted's. This, and some very scary scenes in the haunted forest, led to its PG rating.

This movie, has the highest number of Academy Award nominations for a Harry Potter movie, totaling three. The other entry to do this, was the final film in the franchise, Harry Potter and the Deathly Hallows: Part 2 (2011). This is the only Harry Potter movie to be Oscar nominated for Best Costume.

The street that Harry and Hagrid walk down, to get to the Leaky Cauldron, is the same street on which Sean Connery is parked, waiting for Catherine Zeta-Jones to leave the antiques shop in Entrapment (1999).

This movie has the distinction of opening on more screens in the U.S. than any other (3,762).

In the flying lesson, the whistle Madame Hooch is wearing, is called a 'Boatswain's Call' and was originally used in the early Navy (before P.A. systems) to signal an order, because the whistle could be heard from one end of the ship to the other. It is now used in the Navy as a ceremonial whistle.

At one point, Harry mentions that during his trip to London, he heard Hagrid profess his love for dragons and his desire to own one. The scene that Harry describes was filmed, but deleted from the movie.

All of the cars, on Privet Drive, are Vauxhalls, no matter the time period. The Dursleys own a silver 2000 Vauxhall Vectra Estate. All of the other cars parked in the drives, are Vectra Estates in the present day, with Astra, Belmont and Cavalier Saloons from the late 1980s in the pre-titles prologue.

Daniel Radcliffe said that he didn't think that he would play Harry in all of the films, as he believed he wouldn't fit the part, once he got older. However, he went on to star in all eight movies.

Hatty Jones auditioned for Hermione Granger before it went to Emma Watson. She and Emma were the very last girls for the audition.

James Horner was contacted to compose the music for the film, but he was unavailable because of his schedule conflict. The task ultimately went to John Williams.

Steve Kloves was nervous when he first met J.K. Rowling, as he did not want her to think he was going to "[destroy] her baby". Rowling admitted that she "was really ready to hate this Steve Kloves," but recalled her initial meeting with him: "The first time I met him, he said to me, 'You know who my favourite character is?' And I thought, You're gonna say Ron. I know you're gonna say Ron. But he said 'Hermione.' And I just kind of melted."

Daniel Radcliffe was initially meant to wear green contact lenses as his eyes are blue, and not green like Harry's, but the lenses gave Radcliffe extreme irritation, and, upon consultation with J.K. Rowling, it was agreed that Harry could have blue eyes.

Casting Harry Potter was the film's biggest challenge; they saw 5,000 auditions and none of them felt right. Chris Columbus saw Daniel Radcliffe in David Copperfield (1999) and showed it to the casting director, and said Radcliffe was the one, and that he was amazing. But she said they wouldn't get him, because his parents want him to focus on his schoolwork, and not acting, as well as all the attention he'd get. So they interviewed Harry Potter's of different nationalities all over the world and still hadn't found him. She got frustrated with Columbus, because he had his heart set on Radcliffe. By sheer coincidence, the producer and screenwriter of The Philosopher's/Sorcerer's Stone went the theater, and in the front row was Radcliffe, with his father, so they talked, and slowly persuaded him to cast Radcliffe.

Troll (1986) features a character called Harry Potter, who fights trolls, and casts spells. It came out eleven years before J.K. Rowling published "Harry Potter and the Philosopher's/Sorcerer's Stone". J.K. Rowling denies any connection.

Tim Roth was a leading contender for the role of Professor Severus Snape. Roth dropped out of contention, however, to pursue his role as General Thade in Tim Burton's adaptation of Planet of the Apes (2001).

Screenwriter Michael Goldenberg wrote a draft of the script, but was ultimately rejected by David Heyman, in favor of Steve Kloves' draft. Heyman, however, was impressed with his draft, and was subsequently brought in to write the script for Harry Potter and the Order of the Phoenix (2007), when Kloves backed out to commit to a personal project.

The owls used in the film were shipped over from Massachusetts.

For the Gringotts interior scenes, the Australian High Commission in London was used. The exteriors are the Silver Vaults located not far from the Australian High Commission.

The only Harry Potter movie not to feature a stylized version of the Warner Bros. logo, although the film's theme is played over the standard logo, as opposed to the original Warner Bros. theme.

Chris Columbus, remembering his experiences with Macaulay Culkin during the production of Home Alone 2: Lost in New York (1992), would only audition child actors without "stage parents" during casting.

Crabbe and Goyle have no dialogue.

In the original draft, Drew Barrymore, a self-proclaimed Harry Potter fan, had a cameo.

The design for the Great Hall set was based on the hall at Christ Church, Oxford. Oxford University itself also served as a filming location.

Despite having less than a minute of screen time and only two lines of dialogue, the unnamed Head Goblin at Gringotts is featured prominently on the American theatrical poster, right under Ron and Harry's faces. It is thought by many that this is because of his rather striking appearance.

Film debut of Emma Watson.

Emma Watson's Oxford theater teacher passed her name on to the casting agents, and she had to do over five interviews before she got the part. Watson took her audition seriously, but "never really thought I had any chance of getting the role." The producers were impressed by Watson's self-confidence and she outperformed the thousands of other girls who had applied.

Emma Watson has stated that she hates the way her hair looks in this film. In the following films, her hair was made less bushy, and more wavy.

The "Hogwart's Express" locomotive portrayed in this film, a 1937 4-6-0 "Hall" class steam engine number 5972, originally belonged to the Great Western Railway and went under the name of "Olton Hall".

John Williams composed a piece of music specifically for the movie's trailer without having seen a single frame of film, and it is found on the soundtrack as "The Prologue". As of March 2002, he has done this only once before, for Steven Spielberg's Hook (1991). (However, on the collector's edition of the soundtrack for Jaws (1975), a previously unreleased track appears called "Shark Attack" - this was only used in the trailer for that movie - in 1975.)

Despite the objection to the Harry Potter series by certain Christian groups, several historic churches in the UK, including Durham Cathedral, Gloucester Cathedral, Lacock Abbey, Christ Church College Oxford, and in the later films, St. Paul's Cathedral, were used as filming locations for the franchise. They even inspired much of the layout and architectural details of Hogwarts.

Judianna Makovsky re-designed the Quidditch robes, having initially planned to use those shown on the cover of the American book, but deemed them "a mess." Instead, she dressed the Quidditch players in "preppie sweaters, 19th century fencing breeches and arm guards."

Dudley Dursley is played by Harry Melling. There is a brief moment in the film, which was not in the book, in which Hagrid mistakes Dudley for Harry, to which Dudley responds that he's "not Harry."

In the book, Hermione is described as having buck teeth. This was abandoned when Emma Watson couldn't speak with them.

In the troll scene, in the girl's bathroom, Daniel Radcliffe isn't actually on the troll's neck, because the motions would have snapped his neck; therefore, his image was digitally added.

This and Harry Potter and the Chamber of Secrets (2002) are Chris Columbus' two biggest financial hits.

The film cast includes one Oscar winner: Maggie Smith; and four Oscar nominees: Richard Harris, John Hurt, Julie Walters, and John Cleese.

Chris Columbus pitched his vision of the film for two hours, stating that he wanted the Muggle scenes "to be bleak and dreary" but those set in the wizarding world "to be steeped in color, mood, and detail." He took inspiration from Great Expectations (1946) and Oliver Twist (1948), wishing to use "that sort of darkness, that sort of edge, that quality to the cinematography," taking the color designs from Oliver! (1968) and The Godfather (1972).

The highest grossing film of 2001.

Scenes from Chris Columbus' script for Young Sherlock Holmes (1985) were used in auditioning the young actors.

After Steven Spielberg dropped out, he recommended M. Night Shyamalan for the project, but he ultimately turned it down.

Simon Fisher-Becker says he signed a four-picture deal to play the Fat Friar, but this was the only film he did, and nearly all of his role was removed in post-production.

Chris Columbus wanted to work with Director of Photography John Seale, and asked the studio to hire him, but at that time, Seale was committed to shooting Timeline (2003). However, production delays, for the latter film, enabled Seale to be available for this movie's photography period.

Filming started in September 2000, and finished on March 21, 2001.

In the warehouse section of the National Railway Museum in York, there is an apparently authentic and suitably pitted and rusty white-on-orange sign saying "Platform 9 3/4", in the style that British Railways used in the 1950s and 1960s.

Daniel Radcliffe was reportedly paid one million pounds for the film, although he felt the fee was not "that important".

Although Steven Spielberg initially negotiated to direct the film, he declined the offer. Spielberg reportedly wanted the adaptation to be an animated film, with Haley Joel Osment to provide Harry Potter's voice, or a film that incorporated elements from subsequent books as well. Spielberg contended that, in his opinion, it was like "shooting ducks in a barrel. It's just a slam dunk. It's just like withdrawing a billion dollars and putting it into your personal bank accounts. There's no challenge." J.K. Rowling maintains that she had no role in choosing directors for the films, and that "anyone who thinks I could or would have vetoed him (Spielberg) needs their Quick-Quotes Quill serviced." David Heyman recalled that Spielberg decided to direct A.I. Artificial Intelligence (2001) instead.

Much of the stonework around Hogwarts (excluding the areas that were filmed on location) is actually plaster that has been painted and distressed to make it appear as though it is hundreds of years old.

When the directors first came to J.K. Rowling to ask if they could make movies on the entire Harry Potter series, she said yes, but on one condition. She said that as she imagined all the characters to be British, all of the actors have to be British.

There is a painting of Anne Boleyn hanging in Hogwarts, to the right of the staircase just before Harry, Ron, and Hermione encounter Fluffy for the first time. Anne Boleyn was Henry VIII's second wife, beheaded for the supposed crimes of treason, incest, and witchcraft.

Chris Columbus originally planned to use both animatronics and CGI to create the film's magical creatures, including Fluffy.

William Moseley, who was later cast as Peter Pevensie in The Chronicles of Narnia movies, also auditioned for the role of Harry Potter.

In order to understand what he believed to be caretaker Filch's lonely lifestyle, David Bradley and his cat rented an isolated Irish cottage to live in for a month before filming began.

David Heyman began the process of adapting the book into a film before it was even published.

The movie features nearly 600 visual effects shots, involving numerous companies.

Gabriel Thomson was considered for the role of Harry. His My Family (2000) co-star Zoë Wanamaker plays Madame Hooch.

Apart from Peeves the Poltergeist, two other minor characters from the book did not make it into the film. The first is Mrs. Arabella Figg, Harry's friendly elderly neighbor from across the street, who is described in the early chapter of the book. Although she was omitted from the first four movies, she finally appears in Harry Potter and the Order of the Phoenix (2007). The second character to be omitted is Professor Binns, Hogwarts' teacher of History of Magic. The book describes him as the only teacher who is a ghost, seemingly being quite unaware of the fact that he died in his sleep.

For most of the film, the body double for Hagrid would wear a animatronic head that resembled Robbie Coltrane. The head is displayed at the Harry Potter Studios in London.

Caio César, a prominent Brazilian voice actor, who dubbed Daniel Radcliffe as Harry Potter, and in other films, was also a military cop and died at the age of 27 in 2015, after being shot in the neck, at the Complexo do Alemão slums, in Rio de Janeiro.

The ornate ceiling of the Great Hall (including the trusses) was created entirely using CGI. In real-life, the ceiling consisted of nothing but studio stage lighting.

Dancing with the Stars (2005) pros Mark Ballas, Derek Hough, and Julianne Hough made uncredited cameos as Hogwart's students.

Warner Bros. had initially planned to release the film over the July 4, 2001 weekend, making for such a short production window, that several proposed directors pulled themselves out of the running. However, due to time constraints, the date was pushed back to November 16, 2001.

J.K. Rowling made up the names of the four Hogwarts houses while on a plane. She wrote them down on a barf bag (empty, fortunately) so she would remember them.

Steve Kloves described adapting the book as "tough", as it did not "lend itself to adaptation as well as the next two books."

Fluffy the three-headed dog's appearance is physically based on a Staffordshire Bull Terrier.

This is the only Harry Potter movie where Harry does not cast an attacking spell.

John Williams composed the score at his houses in Los Angeles and Tanglewood before recording it in London in August 2001.

When Chris Columbus scripted Young Sherlock Holmes (1985), that film foreshadowed his future association with the Harry Potter series; the teenage Watson resembles Harry Potter; school experiments; Draco Malfoy's rivalry with Harry is similar to one Holmes has with another student, Dudley; Draco and Dudley both come from rich parents; cavernous libraries; sweets; train stations; the novelization uses the word potty/Potter; students being injured and needing to see the school nurse; teachers and students eating in the Great Hall; Holmes, Watson and a third character solving mysteries at school and Harry, Ron and Hermione doing the same at Hogwarts; staircases; Harry/Holmes and Watson creeping through a school library at night; both Watson and Hagrid say "sorry about that"; the end of school term; the threat of expulsion; no family for Harry to return to, even at Christmas; Harry has a scar on his forehead and Holmes has one on his cheek; seemingly innocent teaching staff exposed as the opposite; head boys, etc.

Fluffy the three headed dog is modeled after Cerberus the three-headed dog of the underworld from Greek mythology.

Sir Alec Guinness was considered to play the role of Dumbledore, but he died shortly before filming began.

Once in an interview, Rik Mayall (the voice of Peeves), said he hadn't read the book and claimed that he did to his agent, and it was one of his favorites. On the set, when asked to read his lines, he constantly made the children burst into laughter with his voice, which had got out of hand, and he was asked to turn his back to the kids to read it, which was also useless. Then they asked him to go all the way to the other side of the cathedral, and shout his words, which also caused them to laugh. According to him, Peeves was in the movie, but after a few weeks, they decided to take his scenes out. He said that when his children saw the movie, and came back home, they said to him: "That was bloody good make-up. You didn't look like yourself at all. It was really good." He said that they mistaken him for Hagrid. He also said that the "movie was shit" because he wasn't in it.

Tom Felton originally auditioned for both Harry and Ron, before getting the part of Draco.

Simon Fisher-Becker signed a four-picture deal to play the Fat Friar. However, he only appears in one scene in this film, and not in any others.

Fiona Shaw, who portrays a woman despising the supernatural and witchcraft, in this film, ironically portrays a powerful witch in True Blood (2008).

Daniel Radcliffe's second film.

When Chris Columbus scripted Young Sherlock Holmes (1985), Watson believed Holmes obsessed over a case, even at Christmas, because unlike other boys his age, he had no family to which to go home, like Harry Potter, or Kevin McCallister. Columbus has ties to both the Harry Potter and Home Alone franchises.

John Coppinger stated that the magical creatures that needed to be created for the film had to be designed multiple times.

Robbie Coltrane and Geraldine Somerville had previously costarred in Cracker (1993). However, they have no scenes together here.

In the Wizard Pub, Harry and Hagrid go into the bar, the bartender says, "usual I presume" to Hagrid. This is possibly a reference to the books, where Hagrid would frequently get drunk.

Richard Harris, who had been acting for over 40 years by the time this film entered production, stated that he had never been involved with a cast that was as close as this one.

The first of eight movies based on the Harry Potter book series by J.K. Rowling.

Among the numerous directors who were interested in tackling the film were Simon West, Brad Silberling, Robert Zemeckis, Jonathan Demme, Jan de Bont, and Joel Schumacher.

Chris Columbus released Home Alone (1990) on November 16, 1990, exactly 11 years earlier than this film.

Model Lucy Elgee-Taylor appeared in the background of the scene in the great hall.

Throughout the eight-movie series, five actresses played "Pansy Parkinson": 1-Katherine Nicholson [Harry Potter and the Sorcerer's Stone (2001), and 'Harry Potter and the Chamber of Secrets (2002)', uncredited in both], 2-Genevieve Gaunt ['Harry Potter and the Prisoner of Azkaban (2004)'], 3-'Charlotte Ritchie' ['Harry Potter and the Goblet of Fire (2005)', originally listed as "Student" and uncredited)], 4-Lauren Shotton [Harry Potter and the Order of the Phoenix (2007)' (again uncredited as Pansy], and, 5-Scarlett Byrne in 'Harry Potter and the Half-Blood Prince (2009)', 'Harry Potter and the Deathly Hallows: Part 1 (2010)', and 'Harry Potter and the Deathly Hallows: Part 2 (2011)'.

When Dumbledore is announcing team points, two candles can be seen rapidly floating.

The only "Harry Potter" movie that features a sets of triplets [the Saunders Triplets ("Baby Harry Potter", born 8/30/1999)] and a set of twins [James Phelps and Oliver Phelps ("Fred & George Weasley", respectively, born 2/25/1986)].

This was the first of two (uncredited) appearances for Katherine Nicholson as Pansy Parkinson: Harry Potter and the Sorcerer's Stone (2001), and 'Harry Potter and the Chamber of Secrets (2002)'. She was the first of five actresses to play the role.

Despite many instances of Harry being noted as a "great wizard", Harry does not, in fact, cast a single spell during the entire movie.

Originally, Daniel Radcliffe was supposed to wear colored contact lenses to turn his naturally blue eyes green (as Harry is described in the books as having green eyes), but after suffering an allergic reaction to the lenses, the decision was made to drop them, and Harry's eyes remained blue for the rest of the series. Similarly, Emma Watson was originally going to wear fake teeth (as Hermione is described as having large front teeth) but she couldn't talk clearly with them in, and the teeth were dropped. There is one scene in the film in which Radcliffe and Watson are wearing their respective contact lenses and teeth; it is the final scene in the film where the trio return home on the Hogwarts Express, which actually was the first scene that was filmed.

During Harry's first ever Christmas at Hogwarts, Fred and George bewitched snowballs to zoom at and hit the back of Quirrell's turban. In doing so, they were unknowingly hitting Voldemort in the face.

Hermione performing magic, on the Hogwarts Express, to mend Harry's broken glasses, was not in the book, it was added for the film.

One of Chris Columbus's daughters had trouble reading, until she read Harry Potter and the Sorcerer's Stone in two days, which opened her eyes to the world of books. After reading the Chamber of Secrets, she asked Columbus to make films out of them, but there were fifty other directors already interested. Columbus fell in love with the first two books too, so he sat down with Warner Bros. saying how obsessed he was with making The Sorcerer's Stone more than anything else. Columbus asked to be the last director Warner Bros. saw, which took about ten days. Columbus stayed up until three a.m. rewriting the script each day. It was already a good script, but Columbus wanted to talk about the visuals. He told Warner Bros. he had rewritten the script for free, and that made an impression on them, because that didn't happen in Hollywood, where they have to be paid for everything. Because Columbus had done that without any pressure from Warner Bros., it made the difference, and after subsequent meetings, and five weeks later, he got the job of directing it.

Hermione never flies on a broom, but in the book she flies on a broom with Harry and Ron to catch the flying key.

In the book, Harry, Hermione, Neville, and Malfoy spend a night in the Forbidden Forest, with Hagrid, for the detention, but in the movie, Neville is replaced by Ron.

In the book, Hagrid gave Harry the flute for Christmas, which he later used to lull Fluffy to sleep.

In an extended version of the film, these scenes were added: Aunt Petunia dying Dudley's old uniform gray so Harry could use it as his school uniform. Aunt Petunia opening eggs containing Harry's Hogwarts letters. Harry and Hagrid riding in a train/subway where they talked about Hagrid wanting a dragon for a pet. An extended version of Professor Snape's potion class. After rescuing Hermione from the troll, the trio had a moment wherein Ron said to Hermione, "What are friends for?" During Christmas dinner at the Great Hall, Ron tried to comfort Harry after their experience looking at the Mirror of Erised. Harry, Ron, and Hermione discovered Nicholas Flamel's name in a wizard card while eating at the Great Hall. Also, Ron confronted Neville (because Malfoy had cast a spell on him), that he should learn to stand up for himself, which he did in the end, when he tried to stop the trio from leaving Gryffindor tower.

Behind-the-scenes pictures show a different design for the incarnation of Voldemort that is stuck on the back of the head of Professor Quirrell. This version has much more animalistic features, most prominently a panther-like snout and large jaw filled with big incisors. This was later changed: Ian Hart provided the voice and motion captured Voldemort's face, which was later added with computer graphics. Richard Bremmer portrayed Voldemort in the flashback to the death of Harry's parents.

During the scene where Harry sees his parents in the mirror, it was supposed to be his entire family (according to the book)

On Christmas when you see the sweater Rons mother made him there is a yellow R, but in the book his sweater didn't have a letter. In the book George and Fred come into the room and complain Ron doesnt have a letter. They said "I suppose she thinks you dont forget your name. But we're not stupid-we know we're called Gred and Forge".

The fire trapping Harry in the dungeon with Quirrel/Voldemort was not in the book, but it was based on the coloured fire Harry and Hermione face with the seven potion bottles in the novel after winning the Chess game. The visual effect of the fire surrounding the dungeon was done by pipes placed in the floor around the dungeon set which were lit after Ian Hart snapped his fingers.

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