the Phoenix. It would seem that when one wishes to hide something it produces the same room for everyone: the Room of Hidden Things, which is full of many centuries worth of abandoned objects, such as broken furniture, books, and in one case a dead quintaped (for more information see Fantastic Beasts and Where to Find Them), which were presumably forgotten by their owners. Harry learns of the room's abilities from Dobby in Order of the Phoenix, finding it the perfect location for his Dumbledore's Army meetings, during which it is filled with bookcases full of Defence Against the Dark Arts volumes, many different kinds of Dark Detectors, and a plethora of floor cushions for practising defensive spells. When the D.A. is betrayed, the room is left open, and Pansy Parkinson is able to retrieve the list of members of the organisation. In Half-Blood Prince Harry uses the Room of Hidden Things to stash his copy of Advanced Potion-Making, describing it as the size of a large cathedral and packed to overflowing with items hidden by Hogwarts inhabitants over the years, such as old potions, clothing, ruined furniture, an old tiara (which happens to be one of Voldemort's Horcruxes), or books which are "no doubt banned or graffitied or stolen." He later realises that Draco has been using the room in this state to hide and repair the Vanishing Cabinet to use it to smuggle Death Eaters into Hogwarts. Ironically, while Harry tries many times to get into the Room of Requirement to see what Draco is doing, the only time he succeeds to get into the room (and he is not thinking about Draco), he gains access to the room where Malfoy has been working. In Deathly Hallows, the students who need a place to hide from the Carrows, two Death Eater professors, use the room. It is also revealed that the Room of Requirement's current version can change while still occupied, though should a completely different version be required (e.g. the Room of Hidden Things instead of DA Headquarters) the room must be empty. The Room can also answer to the desire of the wizard within the room, such as providing Harry with a whistle when he needed one during a Dumbledore's Army meeting, or creating a passage to the Hog's Head (as the room cannot produce food). Later, Ravenclaw's diadem is found to be one of Voldemort's