From MTG Salvation Wiki
Lumengrid, Seat of the Synod. Art by John Avon.
Lumengrid,
Seat of the Synod, is a massive city-stronghold on
Mirrodin where the
vedalken lived. It was a center of technology and artifice on the plane, rising above the
Quicksilver Sea on a massive cylinder with a mushroom-like dome at its top. The Synod, a gathering of vedalken rulers and officials, was housed here, along with the
Pool of Knowledge. This was also the primary area inhabited by common vedalken.
Neurok from the coast of the Quicksilver Sea were brought here to help with lab work, exploration of the plane, or to work as slaves, as well as various other exploits of the Vedalken Empire. It was guarded by
drones and a few Neurok guards.