The Hollow Mountain is the common name for the Forbidden Fortress on Terra, the secret complex that houses the Astronomican and the Adeptus Astronomica. It’s one of the most vital sites in the Imperium, and almost nobody is allowed inside.
Overview
The Hollow Mountain is another name for the Forbidden Fortress, also called the Fortress of the Astronomican. It’s a vast, hidden complex built into the Himalazia mountains on Terra, and it’s the base of the Adeptus Astronomica.
From the outside, the mountains look untouched. In reality, the fortress extends deep into the rock and runs through the entire range. At its heart is the Chamber of the Astronomican, a massive sphere carved into a single mountain, with the peak shaped to form its upper half.
Why it matters
The Hollow Mountain is where the Astronomican is generated. That’s the psychic beacon that guides Imperial ships through the Warp, so without it, interstellar travel would collapse.
The fortress also holds the Chamber of the Astronomican, where a thousand psykers are sacrificed daily to power the beacon. Their deaths keep the light burning.
The complex is protected by grey-clad guardians of the Adeptus Astronomica, and access is extremely restricted. Even Inquisitors and Adeptus Arbites need permission to enter.
- Houses the Astronomican, the Imperium’s navigation beacon.
- A thousand psykers are sacrificed daily to fuel it.
- Guarded by the Adeptus Astronomica; entry requires permission even for Inquisitors.
- Linked directly to the Golden Throne via massive cables.
Layout and defenses
The fortress is more than just a chamber. Around it are city-sized emitters that broadcast the Astronomican’s power across the Imperium. Together, they’re roughly the size of the Imperial Palace.
The power conduits run all the way back to the Golden Throne, carried along a trench hundreds of kilometers deep. That trench is lined with Mechanicum equipment, gun batteries, and Void Shield arrays.
Tech-Priests of the Mechanicum constantly maintain this ancient and degrading technology. It’s a full-time job keeping the whole network running.
The Hollow Mountain in the lore
The fortress was built by the Emperor at some unspecified point in the distant past. It’s been a secret for most of its existence.
During the Noctis Aeterna and the daemonic incursion on Terra, the Forbidden Fortress was attacked by the Warp. Its adepts went mad, and many were possessed. Inquisitor Erasmus Crowl and his retinue arrived to find the site in chaos.
Imperial Fists reinforcements soon arrived and purged the daemonic infestation. The event is depicted in the novel Vaults of Terra: The Hollow Mountain by Chris Wraight, the second book in the Vaults of Terra series.
Key facts
- The Hollow Mountain is the Forbidden Fortress, home of the Astronomican.
- It’s located in the Himalazia mountains on Terra.
- A thousand psykers are sacrificed daily to power the Astronomican.
- The fortress is linked to the Golden Throne by massive cables.
- It was attacked by daemons during the Noctis Aeterna.
- It appears in the novel Vaults of Terra: The Hollow Mountain by Chris Wraight.
FAQ
What is the Hollow Mountain?
It’s another name for the Forbidden Fortress, the secret complex on Terra that houses the Astronomican and the Adeptus Astronomica.
Why is it called the Hollow Mountain?
Because the fortress is built deep inside the Himalazia mountains, making them effectively hollow. The Chamber of the Astronomican is carved into a single peak.
Can anyone visit the Hollow Mountain?
No. Access is heavily restricted. Even Inquisitors and Adeptus Arbites must get permission before entering.
What happened during the Noctis Aeterna?
The fortress was attacked by daemonic forces. Its adepts went mad or were possessed, and Imperial Fists had to purge the complex.