Forbidden Corridor

• Type: Corridor
• Location: Third floor, right-hand side, Hogwarts Castle, Scotland
• Owner/Residents: Hogwarts School of Witchcraft and Wizardry; temporarily guarded by Fluffy
• Key Features: A locked and forbidden area designed to house a series of magical protections for the Philosopher's Stone during the 1991-1992 school year.

The Forbidden Corridor was a specific corridor located on the third floor of Hogwarts Castle. For the duration of the 1991-1992 school year, it was declared strictly out of bounds by Headmaster Albus Dumbledore. At the start-of-term feast, he issued a warning that the corridor was forbidden to “everyone who does not wish to die a very painful death.” The corridor itself was unremarkable, but at its end was a locked door. Behind this door lay a series of seven chambers, each containing a complex magical obstacle or creature. These protections were established by various Hogwarts professors to guard the Philosopher's Stone, which Dumbledore had moved from its vault at Gringotts Wizarding Bank to the castle for safekeeping from Lord Voldemort. After Harry Potter thwarted Professor Quirrell's attempt to steal the Stone and Nicolas Flamel agreed to its destruction, the protections within the corridor were dismantled. The corridor was subsequently reopened and returned to normal use within the castle.

The Forbidden Corridor is a central location and plot device in Harry Potter and the Philosopher's Stone. Dumbledore's ominous warning immediately makes it a subject of intense curiosity for Harry Potter, Ron Weasley, and Hermione Granger. The trio first stumbles into the corridor by accident while fleeing from Argus Filch and his cat, Mrs Norris, after a planned midnight duel with Draco Malfoy goes awry. They get past the locked door with an Alohomora charm cast by Hermione and come face-to-face with Fluffy, a monstrous three-headed dog guarding a trapdoor. This encounter sparks their investigation into what the dog is guarding, a mystery that drives the narrative of the first book. Their belief that Professor Snape is trying to steal the hidden object leads them to brave the corridor's challenges near the end of the school year. The journey through the various chambers serves as a critical test of their friendship, courage, and individual skills. The corridor is the setting for the book's climax, where Harry discovers the truth about Professor Quirrell's allegiance to Lord Voldemort and ultimately protects the Philosopher's Stone.

The corridor served as an entrance to a sequence of seven magical chambers, each with a unique challenge created by a different professor.

1. The Three-Headed Dog: A chamber containing Fluffy, a giant three-headed dog belonging to Rubeus Hagrid. Fluffy stood guard over a trapdoor and could be lulled to sleep with music. Professor Quirrell used an enchanted harp, while the trio used a wooden flute Hagrid had given to Harry.
2. The Devil's Snare: A dark, damp chamber filled with a large Devil's Snare plant, placed by Professor Sprout. The plant ensnares anyone who enters its space, but it is vulnerable to sunlight and fire. Hermione Granger defeated it by conjuring a jet of bluebell flames.
3. The Chamber of Winged Keys: A high-ceilinged chamber containing hundreds of flying keys, an enchantment by Professor Flitwick. To pass, one had to catch the specific key that would unlock the door to the next room. Harry, a talented Seeker, used a broomstick to catch the correct key, which was old, silver, and had a bent wing.
4. The Wizard's Chessboard: A chamber containing a life-sized Wizard's Chess set, transfigured by Professor McGonagall. To cross the room, one had to take the place of a piece and win the game. Ron Weasley's strategic expertise allowed him to lead them to victory by sacrificing himself as the knight piece.
5. The Mountain Troll: A chamber containing a large Mountain Troll. This was Professor Quirrell's contribution to the protections. However, when the trio arrived, the troll had already been knocked unconscious by Quirrell himself on his way to the final chamber.
6. The Potions Riddle: A room containing a table with seven bottles and a logic puzzle written on a scroll, a challenge devised by Professor Snape. The riddle required careful deduction to identify the single potion that allowed safe passage forward, while others contained poison or harmless nettle wine. Hermione's intellect was crucial in solving it.
7. The Mirror of Erised: The final chamber, containing only the Mirror of Erised. This was Albus Dumbledore's own powerful protection. He had enchanted the mirror so that only a person who wanted to find the Philosopher's Stone, but not use it for personal gain, could retrieve it. This proved to be the perfect defense against Voldemort's greed.

• In the film adaptation, Harry Potter and the Philosopher's Stone, several of the challenges within the corridor are altered or omitted for pacing. (film)
• The Potions Riddle created by Professor Snape and the chamber containing the troll are both completely removed from the film's sequence of events. (film)
• In the book, Hermione defeats the Devil's Snare with a portable, waterproof bluebell flame she conjures in a jar. In the film, she uses the Lumos Solem spell, which is an incantation unique to the cinematic adaptation. (film)