The Vizierate is headquartered at the Vizierate Tower, notionally the residence and base of the Grand Vizier, although Dicard mentions as a random fact that the Grand Vizier is as likely to be at the Black Palace as in the Tower (as if they were old buddies; Oliver’s fairly sure they aren’t.)

The Vizierate Tower itself is an imposing structure, an insanely tall round tower of mirrored glass and steel, dominating the landscape by being built on a hill at the head of a valley.  At its foot lies Purpleton, a settlement grown up to house and support the business of Tower and Vizierate.