Step of Silence

The Step of Silence is a massive chamber inside the Sanctum of the Hierarchs of High Charity, specially designated for the High Prophets. The Step of Silence is a large, round room with an illuminated pedestal in the center. Suspended from the ceiling are hundreds of shards of glass, each a piece of a planet that has been glassed by the Covenant. On the perimeter of the room, there is space for three hundred Honor Guard Elites, should a Prophet be present.

Trivia
The first time the High Prophet of Truth and Tartarus make an appearance in the story is during a private meetings in this room, during the last chapter of Halo: First Strike. They discuss the events that took place on Installation 04, as well as the fate of the future Arbiter and Operation: FIRST STRIKE.

The Step of Silence can be seen in the game during the level High Charity. If the player looks up in a certain room, he/she will see dozens of glowing blue/green shards hanging from the ceiling. There are exactly 76 shards in all — 19 shards in 4 rows. Each of these shards represents 1 planet Glassed by the Covenant.

During the level Cortana in Halo 3, the part of the level where you rescue Cortana from the Statis Field bears strong resemblence to the Step of Silence - the pedestal in the center of the room is distinctly recognizable, even though features such as the sharded roof and glass window are not present because the Flood destroyed them and instead either filled the area with large amounts of biomass or simply left a hole there. The doors on each side of the room are recognizable too, if one paid attention to the geometry of the room during Halo 2, when the character was in the only mildly Flood-infested Step of Silence.