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SITE 3 - "Site 3 is the ground level access point to the original subterranean Mars base structure. Research objects from the lower levels are analyzed and studied in this facility."

Site 3: Analysis Facility is the twenty-fourth level of Doom 3. Sabaoth is now defeated, and the only objective remaining is to stop the invasion completely. With the help of a survivor who provides security clearances and further research logs, the player makes their way to the Caverns where the second active Hellhole is located. This is where archaeological entities are brought to, and where the research is done. This is the last level where the surface of Mars is visible.


  • Elevator 1
  • Site 3 Entrance Hall
  • Site 3 Hub
  • Freight Terminal Access
  • Freight Cart Terminal
  • Artifact Receiving
  • Lab Section 1
  • Lab Section 2
  • Artifact Research
  • Elevator Access
  • Site 3 Area
  • Maintenance 2 Access
  • Maintenance 2
  • Maintenance 2 Closet
  • Freight Control Access
  • Freight Control Tower
  • Maintenance 2 Lower
  • Pit Elevator


You start in a straight corridor, with a Health Station to your left. Walk a bit and a Hell Knight appears in front of you. Kill him and a Wraith teleports at the start point, alongside an Imp and another Wraith at the bottom of the corridor. The right door is sealed, you can only take the left one.

As you pass the door to the Site 3 Hub, a Cacodemon breaks a wind and an Imp teleports near the door, in corridor's side. Walk a bit, a second Cacodemon will teleport at the end of the room, and walking even further cause a Hell Knight to teleport near a Health Station. There are also 2 Clips, 2 Shell Clips, 2 Cell packs, an Ammo Belt and an Armor here, and a locked door. Enter in the door marked "Garage."

The door leads to a tiny hallway and to a big garage. You can hear a Cacodemon waiting for you on the right side. If you walk a bit, the lights turn red and 3 Wraiths teleport in: two in this room, and one in the hub. If you retreat to the hub, an Imp teleports in the tiny hallway. And if you walk down the stairs in the garage, a Hell Knight teleports in. There are a Health Station, 5 Cell packs, an Armor and an Ammo Belt here. Pass the door. You won't be able to go back for some time after this.

You are now in a dark room with some candles floating around. As you walk, the floor collapses and the entire room transforms into some satanic sacrifice room, with an Arch-vile teleporting in, summoning Imps. There is a Medkit near the sacrificial thingy.

The next room is well-lit, thanks to a strange glowing container. A Revenant will come from the stairs on the right. There is a Health Station on the left. If you walk toward stairs, a Maggot runs at you from them, and an Imp comes from the sacrifice room behind. Downstairs are a Clip and an Ammo Belt. Upstairs is a door behind which a Wraith awaits you.

Behind the door are corridors, with a ladder, which are part of a larger control room. A Maggot and an Imp lurks here down the ladder. In the control room, a pair of Imps shoot at you from the walkway and the control screen. Kill them, take the PDA, the Ammo Belt, the Medkit and the 2 Shell Clips, and follow the path, until it leads to a door.

The door leads to a straight corridor. A Revenant will come from the bottom, and then a Maggot will run at you from the previous room. After this, 3 Imps will come at you: one from the bottom and two from the left side. Sometimes, only one comes from the left side. Front path leads to a closed door, left path leads to another one (and the third Imp if he didn't come at you), and to a small dark spot with 2 Stimpacks, an Armor and a ladder. You must go here, it leads to a room from where you won't be able to go back without some fierce battles.

The ladder leads to a drop on the the tablets chamber. Approach them to make a Hell Knight and 2 Maggots teleport in. Kill them, enter the cabinet at the end of the room, to meet Pierce Rogers. Take his PDA, his Ammo Belt, his 3 Cell packs, and then exit the cabinet. You won't be able to go back in. Note that if you kill him, an Arch-vile appears at the cabinet's door. A party of five Maggots will appear, one after another, near the tablets, and a final Imp will come from the bottom door, which is locked. Now you have Rogers' PDA, you can unlock it. It leads back to the previous corridor.

You have to return to the hub. From the lab door, just follow the path, turn left (the once "bottom path"), kill the Revenant which appears here, and unlock the door. It leads to the very first hallway of this level. From here, take the front door, to the hub. An Imp will spawn in front of you, and another one at the very starting point. Then, a Revenant will come at you from the bottom of the hub. You have to unlock the bottom door, next to the Health Station.

It leads to a small bridge. Beware of the sniping Imp in heights to the left, next the entrance door. As you walk in, a Maggot will teleport in front of you. A ladder to the right leads to an Armor, a Box of Shells and an Ammo Belt. Take the elevator.

Beware as you arrive upfloor, as a Maggot and a Wraith will "welcome" you. Then, just take the door on the right.

It leads to the disgusting glowing fleshy corridor. Once you drop at the end of the corridor, you can't return. Additionally, a Revenant will attack from the left, and an Imp will come from the right. The Revenant's place shelters 3 Cell Packs and a Medkit. Follow the path. Strangely here, a wall displays blood dripping... in the reverse motion, from floor to roof. Climb the stairs, kill the Cacodemon which teleports in front of you, avoid the crack in the floor with burning fire, and open the door. Beware of the jumping Imp behind. Additionally, a Cacodemon teleports just behind you.

In the storage room, there is an Imp to the left, a Clip, a Shells Clip, 3 Cell Packs, a BFG Cell and a BFG 9000. Then pass through the door.

You are in the freight train control room. Activate the monitor to call the train to the garage. It is used to convey artifacts dug in later levels to this analysis facility. Now you have to backtrack a bit. Beware as you exit the storage room: a pair of Cacodemons will teleport in, one in front of you and the other behind you. As you walk, a part of the floor will burst, opening a new path. Beware as if you fall into, you won't be able to go back here. You won't be able to reach the Revenant's cache either (as the flesh corridor will have a wall in it), so take all goodies you can here, and jump.

You are in pitch black vents. You'll have to face a Maggot, a Wraith and an Imp here. There is also a Medkit on the right side. The front side has another flesh corridor, leading to the room where the elevator was (precisely, to the "sniper Imp" place).

All you have to do now is collect any remaining items, then return to the garage, and take the freight cart. This trip is the last time you'll see Mars surface. The final room has no enemies, but 2 Cell Packs, 3 Clips, an Armor pickup, and a Stimpack can be picked behind the final elevator.


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