Hogwarts occurring is a passage to the Hog's Head bar that formed before the Battle of Hogwarts. Due to the nature of the Room of Requirement, it is possible that several passages to different locations could be accessed from the Room. The three passages out of Hogwarts that Filch does "not" know about are: A further link between two vanishing cabinets, one in the school and the other in Borgin and Burkes in Knockturn Alley presumably worked until "Chamber of Secrets" when Peeves (persuaded by Nearly Headless Nick) smashed the Hogwarts cabinet. The passage was reopened in "Half-Blood Prince" when Draco
Hogwarts staff seen at Hogwarts conversing with Snape at the start-of-term banquet, and then regularly while teaching Defence Against the Dark Arts lessons. During the school's Halloween banquet, Quirrell appears in the Great Hall to warn staff and students of a troll in the dungeons and then he faints, so he can freely make his way to the third-floor corridor where the Stone is hidden. Snape who, apparently, already suspected Quirrell was up to something, goes to the third floor in order to stop him. In later novels, the readers learn that Dumbledore had told Snape to keep an eye on the