Slytherin Dungeon


 * "Our emblem is the serpent, the wisest of creatures; our house colours are emerald green and silver, and our common room lies behind a concealed entrance down in the dungeons. As you’ll see, its windows look out into the depths of the Hogwarts lake. We often see the giant squid swooshing by — and sometimes more interesting creatures. We like to feel that our hangout has the aura of a mysterious, underwater shipwreck."
 * —Description of the dungeons

Slytherin Dungeon, also known as the Slytherin Common Room, served as the common room for students in Slytherin house at Hogwarts School of Witchcraft and Wizardry. In general, it sported several shades of green and the mantle was adorned with a portrait of a serpent (all associated with the house).

Entrance
There is a door on the right side of the Entrance Hall (if coming down the marble staircase facing the front doors of the castle) that is most frequently used by Slytherin students to get to their common room. Behind the door is a set of stone steps which descend deep into the dungeons.

Note that this door is different from the entrance to the narrow staircase that leads down to Snape's office.

The entrance to the common room is located behind a bare stretch of stone wall in the dungeons of Hogwarts Castle. A password is required to enter it; whereupon a passage is revealed leading to the common room.

Common Room

 * "The Slytherin common room was a long, low underground room with rough stone walls and ceiling, from which round, greenish lamps were hanging on chains. A fire was crackling under an elaborately carved mantelpiece ahead of them, and several Slytherins were silhouetted around it in carved chairs."
 * —Description

The common room is a dungeon-like room with greenish lamps and chairs. This dungeon extends partway under the lake, giving the light in the room a green tinge. The common room has lots of low backed black and dark green button-tufted, leather sofas; skulls; and dark wood cupboards. It is decorated with tapestries featuring the adventures of famous Medieval Slytherins. It has quite a grand atmosphere, but also quite a cold one.

The password to the common room changes every fortnight, and it is posted on the noticeboard. Slytherin students are warned never to bring students from other houses into the common room, or to reveal the password. Supposedly, no outsider has entered the common room, though both The Marauders and The Sanguine Sisters claim to have been there (Ayumi excluded as she is a Slytherin).

Dormitories
As Slytherin has the smallest amount of students, being quite selective, it's dormitories are usually outfitted for four students, although the rooms can expand to fit one more bed, if needed.