Chamber of Secrets

• Type: Secret Chamber, Lair
• Location: Deep beneath Hogwarts School of Witchcraft and Wizardry, Scotland
• Owner/Residents: Created by Salazar Slytherin. Later inhabited by his Basilisk. Accessed by Tom Marvolo Riddle and Harry Potter.
• Key Features: Concealed entrance requiring Parseltongue to open, a long subterranean tunnel, a colossal statue of Salazar Slytherin, and defensive enchantments to hide it from discovery.

The Chamber of Secrets is a legendary hidden chamber constructed by Salazar Slytherin, one of the four Hogwarts Founders. According to legend, Slytherin built the Chamber following a fundamental disagreement with the other founders—particularly Godric Gryffindor—over whether to admit Muggle-born students to Hogwarts. Before leaving the school, Slytherin sealed the Chamber, leaving behind a monster—a Basilisk—that only his true heir could control. The heir was prophesied to unleash the monster to purge the school of all those Slytherin deemed unworthy to study magic. For centuries, the Chamber was considered a myth. Its location remained undiscovered until the 1942-1943 school year, when a fifth-year student named Tom Marvolo Riddle, the true heir of Slytherin, found and opened it. Riddle used his ability to speak Parseltongue to control the Basilisk, resulting in the death of a student, Myrtle Warren (Moaning Myrtle). The Ministry of Magic threatened to close Hogwarts, forcing Riddle to seal the Chamber. He framed Rubeus Hagrid and his pet Acromantula, Aragog, for the attacks. The entrance to the Chamber of Secrets is located in the second-floor girls' lavatory, which became known as Moaning Myrtle's Bathroom. One of the copper taps on a sink is etched with a tiny snake. Speaking the Parseltongue word “Open” to it causes the sink to move aside, revealing a large pipe wide enough for a person to slide down. This pipe leads to a dark, stone tunnel far below the castle, littered with the skeletons of small animals. The tunnel ends at a solid wall carved with two entwined stone serpents with emeralds for eyes, which serves as a second door that also requires Parseltongue to open. Beyond this door lies the main Chamber. It is described as a long, high, and dimly lit room with an eerie greenish glow. Stone pillars carved with more entwined serpents line the path, rising to a ceiling lost in darkness. At the far end stands a colossal, “ancient and monkey-like” statue of Salazar Slytherin, with a long beard that reaches the hem of his stone robes. The Basilisk resided within this statue, emerging from its mouth on the command of the Heir of Slytherin.

The Chamber of Secrets is the central setting and mystery of Harry Potter and the Chamber of Secrets. Harry Potter first learns of the legend from Professor Binns after the Basilisk is unleashed for a second time by the memory of Tom Riddle, acting through a bewitched Ginny Weasley. The monster petrifies several victims, including Mrs. Norris, Colin Creevey, Justin Finch-Fletchley, Nearly Headless Nick, Penelope Clearwater, and Hermione Granger. With help from Ron Weasley and information from Hermione, Harry discovers the entrance in Moaning Myrtle's Bathroom. He enters the Chamber to rescue Ginny, where he confronts the memory of sixteen-year-old Tom Riddle. Riddle reveals his true identity as the future Lord Voldemort and summons the Basilisk. Harry, aided by Dumbledore's phoenix, Fawkes, and the Sword of Gryffindor, successfully slays the Basilisk. He then uses one of its venomous fangs to destroy Tom Riddle's Diary, which is later revealed to be one of Voldemort's Horcruxes. The Chamber reappears in Harry Potter and the Deathly Hallows during the Battle of Hogwarts. Ron Weasley and Hermione Granger go to the Chamber to retrieve Basilisk fangs, knowing the venom is one of the few substances capable of destroying Horcruxes. Ron successfully opens the entrance by mimicking the Parseltongue sounds he heard Harry make. They retrieve several fangs from the Basilisk's skeleton, and Hermione uses one to destroy Hufflepuff's Cup.

• Moaning Myrtle's Bathroom: The location of the secret entrance.
• Entrance Pipe and Tunnel: A long, dark slide and tunnel system leading from the bathroom deep into the dungeons.
• Antechamber Door: A wall carved with two entwined serpents that opens with Parseltongue.
• Main Chamber: The final, vast chamber containing the statue of Salazar Slytherin and the remains of the Basilisk.

• Design in the Films: The film adaptation of Harry Potter and the Chamber of Secrets depicts the Chamber largely as described in the novel, featuring massive snake-headed statues, a flooded floor, and a colossal statue of Slytherin. The entrance pipe is portrayed as a long, twisting slide. (film)
• Plumbing at Hogwarts: J.K. Rowling explained on Pottermore that the Chamber was created long before Hogwarts had modern plumbing. When a plumbing system was installed in the eighteenth century, a Slytherin descendant and Hogwarts student named Corvinus Gaunt knew of the Chamber's entrance and ensured it was preserved and incorporated into the new pipework of the girls' bathroom built on that spot. (Pottermore)