The level of the Ministry of Magic housing the Department of Mysteries (OP7).
The Department of Mysteries is accessed via the lifts from the Atrium. A simple, bare corridor leads to a plain black door. This door opens into the circular room with twelve plain, black, handleless doors all around it. The room is lit with candles burning blue. The floor is polished so that it almost looks like standing water. When the door to the circular room is closed, the walls of the room revolve rapidly, making it impossible to determine which door is which. The doors open easily with a push out.
Rooms on Level nine:
The Brain Room
This long, rectangular room is lit by lamps hanging low on golden chains from the ceiling. It is quite empty except for a few desks surrounding an enormous glass tank of deep green liquid. In this tank a number of pearly-white brains drift around. Other doors open off this room (OP34, OP35).
The Death Chamber
(OP36) This room quite large and also rectangular. It is dimly lit. In the center is a sunken stone pit some twenty feet deep. Stone benches run all around the room and descend in steep steps toward a raised stone dais in the centre of the pit. An ancient, crumbling stone archway, unsupported by any surrounding wall, stands on this dais. This archway is hung with a tattered black curtain which flutters very slightly as though it had just been touched, although the air in the room is still and cold (OP34).
The Hall of Prophecy
(OP37) The Hall of Prophecy, which is entered through the entered through the Time Room, is a vast cold chamber, high as a church, filled with row upon row of towering shelves holding little glass orbs. The row of shelves directly in front of the door from the Time Room is number 53. Number 54 is to the right of that, then 55, and so on. The light is very dim in the Hall. The candles are located on either end of each row, which means that from one end, the far end of each row is lost in darkness. The Prophecy about Harry was located a short distance down row 97 (OP34).
The Locked Room
The door to this room is locked and no spell or magical device appears to work to open it (OP34).
The Planet Room
This is a dark room full of planets, which even Luna Lovegood calls “a very odd place”. Apparently something like the anti-gravity mist from the Triwizard maze is in operation at least part of the time, since people who have entered the room have reported that some of the time they were just floating in the dark (OP35).
The Time Room
This room is filled with beautiful, dancing, diamond-sparkling light. Clocks can be found on every surface, “large and small, grandfather and carriage, hanging in spaces between the bookcases or standing on desks ranging the length of the room, so that a busy, relentless ticking fill[s] the place like thousands of minuscule, marching footsteps (OP34).” A huge crystal bell jar stands at the far end of the room, and it is from this that the sparkling light comes. The bell jar stands on a desk and appears to be full of a billowing, glittering wind. Inside the jar, rising and falling on the glittering current, a tiny object moves through an endless loop. The object is a small humming bird, but it isn’t always a bird. At the bottom of its circuit, the bird is within its egg. As it rises, it hatches and grows into a mature bird by the time it reaches the apex of its path. On the way back down, it becomes a fledgling bird and then reenters its egg, which reforms around it. This progression of time repeats over and over within the jar. A large glass-fronted case stands against a wall within which many Time-Turners of various sizes rest on shelves. The path through this room, toward the bell jar, is a narrow passage between the many desks. At the far end, where the Time-Turners are located, is another door which pushes to open.
In the Department of Mysteries, witches and wizards called Unspeakables go about researching some of the deepest mysteries of existence. The Unspeakables explore and experiment with these mysterious forces in various chambers which are clustered around a circular room lined with doors.
Although there are old courtrooms on a lower floor, the Ministry lifts only go down as far as Level nine. A single black door at the end of the lift corridor provides access to the Department of Mysteries; a staircase to the left of the lift leads to level Ten (OP7).
The voice that accompanies the Ministry lifts typically names a few of the divisions within that department when it a arrives at a floor. For level nine, however, the voice merely announces that it is the Department of Mysteries and does not say anything further (OP7, OP34).
The individual known rooms within the Department of Mysteries have their own pages. Please visit these pages for more details specific to each particular room.