Dungeon

A Dungeon in Sword Art Online is a labyrinth that has numerous paths, monsters, and rooms.

In Aincrad, dungeons are found on every floor. They are tower-like structures that connect each floor to next. The Boss Room of a dungeon must be found and cleared before the stairs to the next floor are opened.

Strategy
Dungeons in Sword Art Online are literally mazes, full of difficult winding paths, traps, hidden rooms, and dead ends. Because of the difficulty of the paths, it often takes Front Line players a week to "map" the dungeon on average, before the Boss Room is found.

At that point, Front Line players typically hold a meeting to strategize the Boss Battle. Several expeditionary parties are sent to gather information on the Boss before a real raid is attempted.

Between the Closed Beta Test and the Official Release, the dungeon maps were likely changed, since it took more than a month for the first floor Boss Room to be located.

Safe Areas
Most dungeons have a handful of safe areas, where monsters do not enter. They can be recognized by a special colored torch placed in the four corners on the wall. Although it is possible to stay in safe areas for several days on end, it is described as a particularly discomforting and sleepless experience, since nearby monster footsteps or growls can be heard frequently.



Boss Rooms
Every dungeon has a boss room. It is usually seen as a large, enormous door set against a wall or dead-end. In the poor-lighting in most dungeons, only by entering do the rooms lit up completly, they are often difficult to make out otherwise. Bosses normally never leave their Boss Rooms. After a boss is defeated once, it will never re-spawns.

Anti-Crystal Field
One of the most lethal (but rare) traps in Aincrad's dungeons is the Anti-Crystal Field trap. It gives off a red color that prevents the usage of any crystals, including teleport crystals. As a result, players who enter anti-crystal field rooms are forced to defeat all enemies or face death. Beginning on the 74th Floor, Boss Rooms were also anti-crystal fields.