"If you'd like to see what the diadem's supposed to look like, I could take you up to our common room and show you, Harry? Ravenclaw's wearing it in her statue."
--Cho Chang (DH29)
The entrance is a door at the top of a tightly winding spiral staircase that leads up from the fifth floor. The old, wooden door has neither handle nor keyhole, but a talking bronze knocker in the shape of an eagle. Rather than asking for a conventional password, the knocker will ask a question; if answered correctly, the knocker will compliment the person on the answer and the door will swing open (DH29).
The common room, like the other house common rooms, is decorated in House colours (blue and bronze silk wall hangings, in this case, and a midnight-blue carpet decorated with stars). The room is wide, circular, and very airy, with a domed ceiling painted with stars to match the carpet, and walls with graceful arched windows that provide a spectacular view of the surrounding mountains. There are bookcases, tables, and chairs, and opposite the entrance is another door leading to the dormitories. Beside this door is a plinth on which stands a life-size statue in white marble of Rowena Ravenclaw wearing her diadem (DH29).
From the Web
Ambient sounds of Ravenclaw common room on Ambientmixer.com