There are a few important things to note about this most unpredictable school...

It’s up a mountain

A very tall mountain, surrounded by forests and accessible only by boat. That’s how the first-years arrive on 1 September – collected off the Hogwarts Express by Hagrid, they travel across a glassily still lake and through a curtain of ivy to a pebbly underground harbour.

It’s a safe place

Maybe even safer than the goblin-staffed wizard bank Gringotts, according to Hagrid – and he says Gringotts is the safest place in the world. As long as you don’t find yourself in its out-of-bounds corridors…

There are four Hogwarts houses

Slytherin turns out Dark witches and wizards, Hufflepuff is for duffers, everyone wants to be in Gryffindor, and Ravenclaw’s not that bad – that’s if you listen to Hagrid, Malfoy, Hermione and Ron. The Sorting Hat is more reliable, telling us that Gryffindors are daring, Hufflepuffs are loyal, Ravenclaws are witty and Slytherins are cunning.

It’s home to ‘about twenty ghosts’…

… and one poltergeist called Peeves. Each house has its own ghost – Gryffindor’s is Sir Nicholas de Mimsy-Porpington, aka Nearly Headless Nick. Sharing a school with ghosts that glide through doors is tricky, but Peeves is the worst. His practical jokes and gleeful pursuit of first-years is enough to make anyone late.

The common rooms are amazing

Well, they are if we go by Gryffindor’s. Located in a tower, reached by a series of staircases, the Gryffindor common room is round and comfortable, and leads to dormitories full of curtained four-poster beds. What luxury.

It has 142 staircases

Stairs at Hogwarts are not straightforward. The 142 staircases vary in shape, size and destination. There are wide ones, narrow ones, some with vanishing steps and others that lead somewhere different on a Friday. Not helpful when you’re trying to stick to a timetable.

Not all the doors are doors

Hogwarts’ doors aren’t much better. Some won’t open unless you ask politely, some like to be tickled and some aren’t doors at all, ‘but solid walls just pretending’. Others lead to disused rooms that house mysterious objects, like the Mirror of Erised.

The teachers are… eccentric

The teaching staff are as varied as their subjects – from History of Magic’s Professor Binns, the only ghost, to the tiny Charms teacher Professor Flitwick. Professor McGonagall is strict but fair; Professor Snape is strict but much less fair. For an expert in the Dark Arts, Professor Quirrell is a bundle of nerves and Dumbledore is, well, a genius who is also ‘a bit mad’.

As are the other staff…

School caretaker Argus Filch and his cat, Mrs Norris, have a strong dislike of Hogwarts students, but Hagrid – Keeper of Keys – more than makes up for it. He lives in a hut on the school grounds and Fang, his giant black boarhound, is much friendlier than Mrs Norris.

People in pictures won’t stay put

Hogwarts’ walls are covered with paintings and portraits, the subjects of which move freely from frame to frame. Gryffindor’s common room is guarded by the Fat Lady, in her pink silk dress. If that wasn’t enough, the antique suits of armour like to wander about as well.

The grounds are as unpredictable as the castle

Hogwarts’ grounds are full of mysterious things – from magical plants in the school greenhouses to creatures lurking in the Forbidden Forest and cavernous tunnels that can comfortably house a mountain troll, the Potions classroom and an underground harbour.

The great feasts

The Great Hall, with its enchanted ceiling, is a centre of feasting excellence. The breakfasts are incredible, but it’s the special occasions you want to look out for. Every kind of food you could possibly imagine appears on those tables. Even mint humbugs.

It has its own owlery

Students’ letters are delivered by owls that stay in the Hogwarts owlery, which is one post office we wouldn’t mind queuing up for.

The library’s Restricted Section has an incredible warning system

Hogwarts’ library contains books about seriously nasty magic, available to students studying advanced Defence Against the Dark Arts. If you get one down from the shelf without permission, it will quite simply scream at you.

It can get very cold – and very hot

Snape’s Potions lessons are taught in the dungeons, which are particularly cold in the winter months. The corridors can be draughty, and the classrooms swelteringly hot in summer. So, not even magic can save Hogwarts’ residents from the vagaries of the British climate.