Mars City (Location)

Mars City is a base of the UAC located on Mars, constructed 25 years before the events of Doom 3. Highly trained Marines and a new unit called Mars-Security, regular guards of the base, protect it. Mars City houses the Marine Headquarters, all in the command of Sergeant Kelly. Mars City has plenty of office space, labs, In-Base Communications, a Break Room, a Medical Area, and its own Armory. Mars City is the main facility on Mars, because it has the only boarding area, so you can leave or enter Mars. Mars City even has its own Underground Maintance Area. Mars City even has its own operational Sentry Bots. Mars City also has an elevator that leads to the Monorail Station. For fun, Mars City has a Arcade machine: Super Turbo Turkey Puncher 3. The Entire Facility houses these different places.

Mars City Underground
Mars City Underground is what keeps Mars City operational. It has many Storage space, power, and its own Communications Arrays. Most of the workers are freaked out going down there. Before you enter the area, there is a security checkpoint in control of T. Brooks. Mars City Underground also has an airlock that leads to the Mars Surface.

Administration
Administration houses the UAC Board directive on Mars and is the main reporting site for all workers.

Alpha Labs
The Alpha Labs are a research lab built in the year 2130. Its main focus is to create technologies like the EPD or the Hydrocon. Divided into 4 sectors, these Labs managed to create some of the most astonishing technologies ever seen.

Enpro Plant
The Enpro Plant is a plant dedicated to power energy to Mars city and to create the Plasma Cells necessary for the Plasma Rifle. A huge Core powers the entire plant.

Communications Transfer
Communications transfer is a shortway between the communications room and the Enpro plant. The Oxygen tanks are held there after many pressure failures occurred.

Communications Room
The Communication Room is the main comms room. Its satelites are automatically connected with UAC-Earth and work together with the redirectioning station Phobos.

Recycling Plant
The recycling plant is perhaps, one of the most important facilities in Mars. Its main focus is to recycle the waste products of the Mars base. It is divided into two sectors, the last one making Betruger his personal Introduction to the Marine.

Monorail
The Monorail is a station that houses the monorail train. It is used to transfer personnel from the Recycling plant to Area 2 or to the Delta Labs. The Main entrance to the Delta Labs is housed by an Automatic turret, which can be disconnected in the security room.

Delta Labs
The Delta Labs is the most advanced research complex in Mars. It houses 4 sectors and the Third Generation Teleporter, which is the origin of the Invasion at the beginning of the Game.

CPU Complex
The CPU Complex manages the entire informatic operations on all Mars.

Site 3
Site 3 is the picking place of all archeological discoveries and artifacts from the Caverns.

Caverns
The Caverns are the first installations ever made on Mars. Its main focus is to discover archeological artifacts and send them to Site 3.

Main Excavation
The Main Excavation was where the Soul cube and many other relics were found. It also houses the Gateway of Hell and the Cyberdemon.

Trivia

 * When exiting the second level in Doom 3, when it says "You are now leaving" inside the elevator, it says "Click to exit Communications Transfer."