Dark Cathedral
From Tardis Wiki, the free Doctor Who reference
The Dark Cathedral was a portal to the Darksmith Collective's light-less underworld home, beneath the surface on the planet Karagula. Few uninvited visitors survived, except those striking a deal with the Darksmiths themselves.
Inside the Dark Cathedral could be found a library of the Darksmith Collective, which housed the trading registers and contract details of those agreements undertaken by the Collective. Brother Varlos' journal on the Eternity Project was stored here in a secret room. (NSA: The Colour of Darkness)
