Boss Keys, also known as Big Keys, are recurring items in the Legend of Zelda series. These special keys are needed to enter the boss room of a dungeon, and, in some games, are needed to open a dungeon's big chest, in order to obtain the dungeon's item. Contrary to the other big prize of a dungeon guarded by a mini-boss, one must usually solve a puzzle or riddle rather than win a difficult fight to obtain this item. In some games, a Boss Key serves as a dungeon's "master key", and can unlock certain doors other than the door to the boss room. Boss Keys are typically "stored" on a game's Map Screen, but there are exceptions. Some games have other types of keys in place of Boss Keys to open the final area of a dungeon.