The flexibility of the Dungeons & Dragons (D&D) game rules means that Dungeon Masters (DM) are free to create their own fantasy campaign settings. For those who wanted a pre-packaged setting in which to play, TSR, Wizards of the Coast (WotC), and other publishers have created many settings in which D&D games can be based; of these, the Forgotten Realms, an epic fantasy world, has been one of the most successful and critically acclaimed settings. Many campaign settings include standard sword and sorcery environments, while others borrow Asian, Central American, swashbuckling, horror and even space-travel themes.