A Sanctuary is a room attached to some Institutes that is built on unhallowed ground.
The Sanctuary serves as a meeting place for Shadowhunters and Downworlders. Unlike the Institute itself, it is not built on consecrated grounds and are reverse-warded like Portals, making it possible for vampires and demons to step foot in the room. It can also be used to shelter Downworlders who need temporary protection, or to hold Downworlders or demons for interrogation.
For the Downworlders who can enter hallowed grounds, the Sanctuary was typically their entrance instead of the Institute's main doors, though this is not always the case.
The Sanctuaries doors are well-protected and warded; they can only be opened either with a key, kept only by entrusted people of the Clave, by an opening rune with a stele, or—especially for a Sanctuary's inner doors leading to the Institute—by the touch of a Shadowhunter.
Sanctuaries can be found with most Institutes built before the 1960s. When Projection magic was developed in 1958, the need for Sanctuaries diminished—at least for simple meetings, and the Sanctuary is still used for its other purposes. The established Sanctuaries were maintained even long after it fell out of fashion.
The London Institute has a Sanctuary Room.
New York Institute
The New York Institute has a Sanctuary.
Los Angeles Institute
The Los Angeles Institute has a Sanctuary.