Dungeons within UO are located on all Facets. They are explorable areas where characters may encounter any combination of monsters, puzzles, NPCs, or traps. Defeating the monsters and solving the puzzles reward players with various types of treasure; the tougher the monsters/puzzles, the more rewarding the treasure. Some Dungeons are multi layered areas, with stairs or hole like openings that must be used to travel between the levels. Typically, the more levels you encounter in a dungeon, the tougher the monsters and puzzles become. For example, in a single dungeon, a level 1 cavern might have Ettins and Earth Elementals, while a level 4 cavern in the same dungeon might have Ogre Lords and Trolls. Other dungeons may be a single level area- yet contain advanced monsters of extreme difficulty. Caution should always be exercised when exploring new Dungeon areas!
Dungeons need not be the stereotypical setting of medieval stone passages containing cells and torture devices. Some "Dungeons" are sewers, jails, caverns, cities, or castles.