Hogwarts: The Vanishing Cabinet

This cabinet, stored within Hogwarts' Room of Requirement, was a key element in the surprising plot twist of Harry Potter and the Half-Blood Prince. It forms a passageway with a twin cabinet stored in Borgin and Burkes in Knockturn Alley. Draco Malfoy uses this unique linkage to sneak Death Eaters into the castle for a surprise attack on Headmaster Albus Dumbledore, leading to Dumbledore's death at the hands of Severus Snape.