The Harry Potter series has been a worldwide phenomenon for over 20 years now. Ever since Harry Potter and the Philosopher's Stone hit the world's bookshelves in 1997, this magical franchise has enchanted readers and movie-goers everywhere. To this day, new generations of Potterheads are being created thanks to the success of the new Fantastic Beasts series. With the original books established as classics, and their film adaptations still incredibly popular, the Boy Wizard and his Wizarding World seem to be here to stay!

Of course, even the most popular of book and film series aren't perfect as plot holes, typing mistakes, and continuity errors are easy to find if you know where to look. Some Potterheads have even spent hours and hours poring over the books again and again, so it's unsurprising that they'd find errors eventually. J.K. Rowling may be an amazing author, but she's infallible just like the rest of us. While some of the mistakes in the Harry Potter books were easily fixed in later editions, others were so deeply wound into the plot that they've had to stay put, for better or worse. If you're wondering where exactly the mistakes in the Harry Potter series are, don't worry, we've got you covered. Some are pretty obvious upon first reading of the books, but others are a little bit harder to detect. However, none of these errors detract from the fact that the Harry Potter series is pretty incredible, imperfections and all! Here are 25 Ridiculous Mistakes In The Harry Potter Series Only True Fans Noticed:

25 Hagrid And Harry's Detour

If you look closely enough, it's possible to find a plot hole at the very beginning of the first Harry Potter book. As we all know, after Voldemort eliminates Lily and James Potter, Hagrid arrives on the scene to whisk the now-orphaned Harry away.

In the book, it's stated that Hagrid picks Harry up at around sunrise on the morning of November 1st. However, he doesn't drop Harry off at the Dursleys' home until “nearly midnight” that same night. Where did Harry and Hagrid go for those missing hours? Nobody knows!

24 Days And Dates

Throughout the Harry Potter series, various days and dates that are specified by J.K. Rowling simply don't add up. For example, in Philosopher's Stone, it's stated that Harry's birthday of that year (31st July 1991) was on a Tuesday.

However, in the real world, it was on a Wednesday. Later on, it's stated that Harry's Hogwarts classes started on September 2nd, but based on July 31st being a Tuesday, this day would be a Sunday. Why did Harry have classes on the weekend? It doesn't make sense!

23 The Winking Boa Constrictor

One of the most memorable scenes in Harry Potter and the Philosopher's Stone is Harry accidentally letting loose a boa constrictor in a zoo. Harry also has a conversation with his new slithering friend, this being an early hint that he's a Parselmouth. During their exchange of words, well, hisses, the snake supposedly winks at Harry.

However, snakes don't have eyelids. This would make it physically impossible for them to wink. Unless snakes in the Harry Potter universe are somehow biologically different to “real” snakes, this is a pretty major goof!

22 How Many Wands?

When Harry finally gets his Hogwarts letter in the Philosopher's Stone, it comes with a list of magical items that he needs to buy. In the first edition of the books, the item “1 Wand” appears twice, but this was fixed in later copies.

Another typing error that was later fixed was the title of the book “One Thousand Magical Herbs and Fungi.” While it is typed correctly on the shopping list, it's later referred to as “One Hundred Magical Herbs and Fungi.” How many herbs and fungi are there, J.K.? Stop confusing us!

21 Troll In The Dungeon

This particular plot hole in the Philosopher's Stone has been brought up by fans many times. When he discovers that there's a troll in the dungeon, Professor Dumbledore responds by sending all students back to their dormitories.

However, Slytherin House's accommodation is in the dungeon, right next to where the troll is. Dumbledore is sending a whole quarter of his students into the path of danger! Does he really dislike Slytherins that much, or did J.K. Rowling just not think this plan through? Hopefully, the latter.

20 Inaccurate Cover Art

The UK editions of the Harry Potter books have featured a couple of notable mistakes when it comes to their cover art. For example, on the original cover of the Philosopher's Stone, Harry is seen wearing a Gryffindor scarf while he's getting on the Hogwarts Express. How does he have that scarf when he hasn't even been sorted yet?

Meanwhile, the first cover of the Chamber of Secrets depicted Hedwig as a barn owl, not a snowy owl. Get your owl species right, guys!

19 Nearly Headless Nick's “Age”

In the original edition of the Chamber of Secrets, some confusion arose with regards to Nearly Headless Nick's “age” – as a ghost, anyway, and in the book, Nick invites Harry to his 500th Deathday Party.

However, in the Philosopher's Stone, the ghostly guardian claimed that he hadn't eaten for nearly 400 years, implying he'd been deceased for that long. That's a hundred-year discrepancy in his age! This error was eventually fixed, though, as in later editions of the first book, “nearly 400 years” was changed to “nearly 500 years.”

18 Unobservant Moaning Myrtle

Harry Potter and the Chamber of Secrets introduced us to Moaning Myrtle, a ghost who lived in the Hogwarts first-floor girls bathroom. In the book, it's revealed that this bathroom contains the entrance to the Chamber of Secrets itself.

Since Myrtle lives in the bathroom, you'd think she'd have spotted Ginny visiting the bathroom under the influence of Tom Riddle, or at least heard the Basilisk moving around in the pipes below her. However, she either saw and heard nothing, or failed to mention these crucial events to Harry. Good one, Myrtle!

17 The Hogwarts Pipes

Speaking of the Basilisk, how on earth did it manage to roam around Hogwarts using the piping system? That snake is pretty darn huge.

The pipes surely couldn't have been wide enough to accommodate it. If they were, the walls of Hogwarts would have been immensely thick! Also, how did the Basilisk get in and out of the pipes when attacking students? These logistical questions have never been answered by J.K. Rowling in the books or elsewhere, and honestly, that’s one pretty big plot hole that needs filling.

16 What's That Hissing?

We've already mentioned that the Basilisk traveled around Hogwarts using the pipes. As it did so, it would hiss, with Harry being able to understand what it was saying thanks to his Parselmouth abilities. He originally thought he was hearing voices, but the truth was much spookier.

Anyway, if Harry could hear the Basilisk “speaking,” why couldn't his fellow students hear loud hissing coming from Hogwarts' walls? Surely, such a big snake would make a reasonably loud noise! We know it was loud enough for Harry to hear it, so why didn't  anybody else pick up on this sound?

15 The Ancestor Of Slytherin

One of the big mysteries in Harry Potter and the Chamber of Secrets is the identity of the heir of Slytherin, with some Hogwarts students suspecting that it is Harry due to his ability to speak Parseltongue. In turn, Harry himself suspects that it is Draco Malfoy.

However, the heir's true identity is revealed at the end of the book as Dumbledore tells Harry that Voldemort is Salazar Slytherin's heir. Well, he does in later editions of the book, at least. In the first edition, a misprint meant that Dumbledore referred to Voldemort as the ancestor of Slytherin! Unless there's some time-travel going on, that's just not possible.

14 The Lunar Calendar

In the Prisoner of Azkaban, Hogwarts gets another new Defence Against the Dark Arts Professor: Remus Lupin. He’s a kind man and a good teacher, but also happens to be a werewolf. A full moon appears every 28 days, meaning Lupin should experience the effects of his lycanthropy around once a month.

However, Lupin's “illnesses,” as described in the book, don't follow that pattern. He seems to experience them as the plot requires, and not at a regular time interval! Sounds like bad planning on J.K. Rowling’s part…

13 Hermione's Time-Turner

Have you ever wanted to take so many classes that you've had to use time travel to get to them? Hermione Granger did just that in the Prisoner of Azkaban using her trusty Time-Turner. It wasn't an easy year for her.

All of that time travel left her visibly exhausted! How did Hermione manage to convince her teachers that using time travel to get to classes was a good idea? It doesn't seem like a healthy or sustainable solution! In fact, having optional classes running at exactly the same time was in itself a poor idea.

12 The Secret-Keeper

During the First Wizarding War, the Potters used the Fidelius Charm to hide their location from Voldemort. The only person who knew where they were was Peter Pettigrew (their Secret-Keeper), but he eventually betrayed them.

However, when the Potters met their demise, everyone assumed that Sirius Black was the Secret-Keeper and thus, the traitor. Since it was Dumbledore who cast the Potters' Fidelius Charm in the first place, wouldn't he have known that Pettigrew was the true Secret-Keeper? Or was the identity of the Secret-Keeper unknown even to the caster of the charm? Nobody knows.

11 Dudley's PlayStation

Dudley Dursley has to be one of the most annoying, spoiled children in fictional history. His parents buy him everything he asks for, but he doesn't seem to show any gratitude whatsoever.

In fact, at the beginning of the Goblet of Fire, Harry tells Sirius that Dudley recently threw his PlayStation out of a window during a tantrum. Problem is, the PlayStation hadn't even been released at the time the book is set in! The Goblet of Fire begins in 1994, and the PlayStation was released in Europe in 1995.

10 Mrs. Weasley's Cooking

Mrs. Weasley is something of a domestic goddess. It must have been pretty challenging for her to look after no less than seven children, even with magic to help her out! She's frequently seen whipping up amazing meals for her brood, as well as for Harry when he's visiting.

However, in the Goblet of Fire, she seems to break one of the rules of magic while cooking. Gamp's Law of Elemental Transfiguration states that food can't be created using magic. Despite this, Mrs. Weasley manages to make a sauce flow from her wand. That shouldn't be possible!

9 The Wand Order Mistake

The so-called “Wand Order Mistake” is well-known among Harry Potter fans. During the duel between Harry and Voldemort at the end of the Goblet of Fire, their wands produce a “Priori Incantatem” effect. This causes “echoes” to appear showing Voldemort's most recent casualties. Their spirits appear from his wand, from the most recent person and onwards.

However, the order of these spirits is wrong. James Potter appears before Lily, despite the fact that he was slain first. Their spirits should appear the other way around!

8 Bellatrix's School Days

In Harry Potter and the Order of the Phoenix, J.K. Rowling made a bit of an error when discussing Bellatrix Lestrange's school days. Sirius tells Harry that Bellatrix and Severus Snape hung out with the same people while they were at school together.

However, this shouldn't be possible due to their respective ages. Bellatrix left Hogwarts in 1970 at the latest, and Snape started his schooling there in 1971. Therefore, they couldn't have been in the same friendship group at school, since their time there didn't overlap at all.

7 Can Prefects Deduct Points?

In the Order of the Phoenix, Ron, Hermione, and Draco all become Prefects, much to the initial annoyance of Harry. As a result they all get new responsibilities, including the ability to deduct House Points – or so Draco claims, anyway!

He deducts points from Hermione when he overhears her badmouthing Professor Umbridge. However, Hufflepuff student Ernie MacMillan then claims that Prefects can't actually deduct points and Draco is talking nonsense. This contradicts the fact that in the  Chamber of Secrets, Percy Weasley takes points away from Ron. So, what's the deal? Can Prefects deduct points or not, J.K.?

6 Harry's Astronomy Exam

Near the end of his fifth year at Hogwarts, Harry (like all of his classmates) takes his OWL exams and one of the subjects he's tested on is Astronomy. As part of the exam, Harry has to go to the Astronomy tower at 11 p.m. and observe various stars and planets. However, some of the “observations” that he makes aren't physically possible.

For example, he supposedly spots the planet Venus at midnight. This is despite the fact that it's only observable at sunrise or sunset. Did Harry forge his observations, or did J.K. Rowling just make a huge astronomy goof? Probably the latter!