The Great Modron Cathedral is a massive structure located in the city of Mechanus, the plane of law and order. It serves as the central hub for the Modrons, mechanical beings that embody the principles of law and hierarchy. The cathedral is known for its intricate architecture, featuring geometric designs and a clockwork mechanism that reflects the precise nature of its inhabitants. Inside the cathedral, various chambers are dedicated to the different ranks of Modrons, each designed to facilitate their orderly functions. The Great Modron Cathedral also acts as a meeting place for Inevitables and other lawful entities, emphasizing the importance of structure and organization in the multiverse.