Location from Deathly Hallows by J.K. Rowling
The hidden room that becomes what you need -- it housed Dumbledore's Army as a resistance base, connected to the Hog's Head for supplies, hid Ravenclaw's diadem for decades, and burned in Fiendfyre.
Also known as: the Room of Requirement, Room of Requirement, the Come and Go Room, Room of Hidden Things