Like any good magic castle, Hogwarts is highly haunted. Each house has its own ghost, with different features and personalities. Slytherin has the Bloody Baron (who is covered in silver bloodstains), Hufflepuff has the Fat Friar, Ravenclaw the Grey Lady, and Gryffindor Nearly Headless Nick. The most useful of Hogwarts’ ghosts is Professor Binns, the school’s History of Magic teacher. One day, he simply fell asleep in front of the fire in the teacher’s quarters, then got up to teach his class the next day, leaving his body behind. He may or may not realize that he’s dead, and enters his lessons through the blackboard.
2. A Pensieve is an object which allows for the sorting and reviewing of memories. The Pensive of Hogwarts is used by the headmasters to review specific memories. Not much is known about its creation except that it is made of stone, carved with Saxon runes, and it is older than the school itself. According to legend, the Pensieve was found by the school’s founders half buried in the ground, and it has become an invaluable tool for headmasters and headmistresses.
3. Once all of the students have arrived, first-years are led into the Great Hall for the Sorting Ceremony. The Sorting Hat then decides which of the four houses each student will be assigned to—Gryffindor, Hufflepuff, Ravenclaw, or Slytherin. The houses are named after the four founding wizards of Hogwarts, and students are sorted according to the different personalities of the founders.
4. Students attending Hogwarts Academy must board the Hogwarts Express train on platform 9 ¾ at King’s Cross station. The train leaves precisely at 11 am on September 1 each year, and it can be accessed by walking through the solid barrier between platforms 9 and 10.
5. James Potter, Sirius Black, Remus Lupin and Peter Pettigrew (known as the Marauders) created the Marauders Map while they were students at Hogwarts. The map is a magical document which exposes every part of Hogwarts, including the secret passages, as well as the location of every person on the grounds, indicated by a dot and their name (though in the movies footsteps were used as indicators instead). The map can’t be fooled by invisibility cloaks or any kind of potion or spell, and can even detect the castle ghosts. The only flaws of the map are that it’s unable to discern the identities of people with similar names (like Barty Crouch Jr./Sr.), and it doesn’t show rooms that are unable to be plotted on a map (like the Room of Requirement).
While it’s known that Hogwarts School is somewhere in Scotland, the exact location is hidden with various charms and spells that make it impossible to discover. If anyone does come across it, all they see is the ruins of a castle with a warning to keep out.
7. The Room of Rewards is a secret room at Hogwarts that records the various accomplishments of the students. The entrance is found behind the portrait of Vindictus Viridian on the Grand Staircase and is a separate room from the Trophy Room.
8. The Hufflepuff Common Room’s entrance is located in the kitchens, concealed behind a pile of barrels in the back right corner. To enter you must tap the right barrel on the bottom row with the rhythm of Helga Hufflepuff—tap tap, tap-tap-tap. If you get it wrong, you get soaked with vinegar.
9. In 1926, the students of Hogwarts were sent home early due to a threat from the dark wizard Gellert Grindelwald. Steps were taken to increase security at the school, but when the Daily Prophet reported the danger, the choice was made to send them home. The School’s permanent closure was considered during both openings of the Chamber of Secrets, but it didn’t end up being shut down either time. Then again, when Dumbledore was murdered, several of the teachers felt that the school should be closed, but the Ministry of Magic’s takeover by Death Eaters forced it to remain open that year under their rule.
10. There are seven required subjects for all first-year students at Hogwarts. They are Transfiguration, Charms, Potions, History of Magic, Defence Against the Dark Arts, Astronomy, and Herbology. Learning how to fly on a broomstick is also required of all students.
11Professor Snape's office
Below the ground floor of Hogwarts are several dungeons. The dungeons are the location for Professor Snape’s office, which was a gloomy room with low light and was “lined with shelves of glass jars” filled with dreadful things. In one corner was a cupboard which contained Snape’s private stock of potion ingredients—a cupboard which was frequently plundered by various characters from the series.
12. The subjects of the portraits hung in Hogwarts are able to move around from portrait to portrait and even visit other portraits of themselves elsewhere in the world. The paintings are generally of witches and warlocks, and thanks to enchantments, can incorporate some of the subject’s favorite phrases and behaviors.
13. In addition to the numerous ghosts that inhabit Hogwarts, there is also a famous and disruptive poltergeist. In the Harry Potter universe, Peeves is the most infamous poltergeist in British history and has “lived” at Hogwarts since 993. Many students and teachers enjoy Peeves, but he is a “pet peeve” for the caretakers at the school who have to clean up his messes. According to Pottermore, there has been many efforts to get rid of Peeves. The most recent (and most calamitous) was in 1876 when the caretaker at the time set a trap baited with weapons he figured Peeves wouldn’t be able to exist. Peeves, of course, managed to steal all the weapons (including cutlasses, crossbows and a cannon) and proceeded to go on a rampage. He only calmed down when school administrators signed a contract with him that allowed him one free swim in the boy's lavatory every week, as well as a new hat.
14. According to Rubeus Hagrid, Hogwarts is the safest place there is in the magical world, even safer than Gringotts, the bank where wizards store their money, which is why the Philosophers’ Stone was kept in the school.
15. Moaning Myrtle’s final resting place is in the first-floor girl’s bathroom above the Great Hall. Myrtle was a Ravenclaw student who was killed by Slytherin’s Basilisk under the order of Tom Riddle (AKA Voldemort). Myrtle haunts the toilet and frequently floods it with her emotional outbursts. It’s described as “gloomy, with cracked and spotty mirrors, and chipped stone sinks.” Due to Myrtle’s depressing presence, girls attending Hogwarts only go in there when absolutely necessary.
Hogwarts Castle has 12 major towers and around 12 smaller ones. The tallest of the towers it the Astronomy tower, where students take their astronomy lessons. It’s also the place where Snape kills Dumbledore. The most mysterious tower is the Dark Tower, which is located at the seventh-floor landing and has a prison cell at its top. It’s made of rough stone, has a stone bench, and shackles for the prisoners.
17. Hogwarts has a solution in case any boys get the idea to enter the girls’ dormitories. The stairs outside the entrance will immediately turn into a slide if boys try to climb them, keeping them from getting in.
18. A portrait of Henry VIII’s wife Anne Boleyn is hung on the wall of the grand staircase near the second-floor landing. She was the Queen consort of England, and mother to Elizabeth I, but Muggles believed that she was a witch. There were also rumors in the Wizarding community that she was a squib—a non-magical child born to magical parents.
19. Salazar Slytherin wanted Hogwarts to admit pure-bloods only, but when the other founders refused to agree to this principle, he chose to leave the school.
20. The Battle of Hogwarts took place in May 1998 within the castle and on the grounds of Hogwarts and was responsible for ending the Second Wizarding War. After the battle, Hogwarts castle was nearly destroyed, but it seemed to have a self-regeneration process and it managed to recover and remain open.
The different staircases in the Grand Staircase reach up to the seventh floor and have a tendency to move within the chamber, often when someone is on them. Certain trick stairs cause the student to sink through them, at which point another person will need to rescue them. First-year students are the most common “victims” of the stairs, as the older students tend to know where the trick ones are and simply jump over them.
22. The first Triwizard tournament was held 300 years after the founding of Hogwarts. The tournament was an interschool competition between the three most prestigious magical schools in Europe—Hogwarts, Beauxbatons, and Durmstrang. It was in part created to allow students from the different schools to interact with one another.
23. A Witch or a Wizard who is born with magical abilities will be automatically enrolled in Hogwarts as soon as they’re born. At age 11, admission is confirmed via owl. If the child has magical abilities but is born to Muggle (human) parents, their parents receive a visit from one of the school’s professors.
24. The school’s motto is Draco Dormiens Nunquam Titillandus, which translated from Latin means “never tickle a sleeping dragon.” When asked how she arrived at the motto, J. K. Rowling explained that she’d always found traditional school slogans about perseverance and nobility boring, and it amused her to use a “practical” piece of advice as the school motto.
25. As soon as they get off the train at Hogsmeade Station, first-year students are led to boats that carry them across the Great Lake. Thestral-drawn carriages transport the older students to the school.