Gil'lornomin, Progress Engine

The Progress Engine is the workhorse of the empire, creating and building the ideas and concepts put forth from the capital. In eight hundred years the engines have never fallen silent in their relentless pursuit of realising the dreams of our people. - Atlas found in Aglarond, The Glittering Chambers

In theory, this place is ~1800 years old, estimated from the Atlas being at least 1000 years old.
An engine that processes Cuithger into anything you'd like using the "Demon Furnace"/"Fiend Engine", which uses the power of Abaddon, the Destroyer  to fuel its power.
Contains:

• The Library of Professor Moreau
• A delightful gift shop
• A lot of scientists offices which may or may not have useful notes in them.

Used to contain the head of Abaddon, the Destroyer but this was removed by Awarth Gurgoth which is Probably Fine
Since the removal of the head, power generation has ceased and the Engine is running on backup batteries.
NPCs - Monitor Chakas, tour guide