It is the place where audiences with the royals are performed, celebrations, and also where all royals, including the Pevensies, are crowned.
After the Telmarines invaded, Cair Paravel fell into ruin, but the ruined outline of the hall remained, and it still showed what was left of the thrones. It was near the Treasure Room, and the Well was to the south of it.
It was described as being very majestic, with an ivory roof, peacock feathers hanging from the west wall, an eastern door that looked out to the sea, and of course four thrones that belonged to the Pevensies.
Each of the four thrones had an emblem etched into the back, which represented one of the Pevensies. Peter's was a replica of his sword, Susan's showed her horn, Lucy her Fire-Flower cordial, and finally Edmund's showed an image of his sword breaking Jadis' wand.
While Edmund's throne emblem clearly shows to be that of a sword breaking a wand, shown by the jagged pieces of the broken wand and the shattered pieces in the emblem, it also resembles that of a set of scales. This is deliberate, as Edmund was also known as Edmund the Just because of his great council and judgement, and the scales represent the scales of justice.
In the film; the Hall appears to be made of marble-stone, with a tiled floor (plain sandy colour and grey pattern tiles), numerous columns that were decorated with gold at the top and bottom, a curved stairway near the entrance that led to an upstairs with balconies with gold railings, open doorways that led to a balcony overlooking the sea, a high dais with several steps that lead up the Pevensies' thrones and a huge stained-glass window behind them, and a glass roof.