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Previous test subjects who have come here have had many questions for us. We answered them with science, fire, and termination.Dr. Dala

The Big MT Research Facility,[2][Non-canon 1] alternately known as Big Mountain Research and Development Center,[Non-canon 2] Big MT, or Big Empty, was a privately owned pre-War defense contractor, industrial site and research center located south of Hopeville in 2281.[3] It serves as the game-world for the Fallout: New Vegas add-on Old World Blues.



The Big MT Research and Development Center was originally built inside a cave system running underneath a large mountain peak that gave it its name.[4] The goal of the facility was to build the future of mankind and create the technology of tomorrow without restraints, either moral or technical. It welcomed some of the most gifted pre-War scientists, who plumbed the depths of many experimental technological fields.[5] The research conducted within was as groundbreaking as it was unethical, conducted in part on living humans (both American volunteers and Chinese-American detainees). Big MT even included a concentration camp of its very own, safeguarded by lucrative contracts with the US Army.[6] However, due to budget cuts in the later years of its operation, Big MT had to improvise alternate means of funding and research. The executives began to strike deals with third parties, exchanging experimental technology for money and other privileges. Due to budget cuts, they even began assassinating non-military targets (Project Hare) to procure research subjects, and exhuming buried US citizens (Project Burke) to procure test subjects.[7]

Due to a failed experiment conducted by the future Doctor Klein in the Y-0 research center, the mountain above the center was vaporized, leaving behind a giant crater and exposing the facility.[8] This catastrophe did not faze the researchers, and the efforts in pushing the boundaries of science continued unabated. The new land exposed by the explosion was adapted for scientific purposes: new facilities were established, both above- and below-ground, including an artillery test field and a test town.

The facility was under the guidance of its six gifted executives, 0, 8, Borous, Dala, Mobius, and the administrator, Klein (their original names unknown[9]) known together as the Think Tank. The facility gave birth to new technologies, such as the Saturnite alloy, next-generation hazmat suits, new models of cyberdogs, advanced stealth suits, holograms, and many more. At the same time, many new horrors were also born in the laboratories of the Big MT: cazadores, night stalkers, mutagenic plants, ambulatory corpses, previously unknown toxins, and other fearsome creations. Both types were sold to private parties in exchange for certain favors: Frederick Sinclair obtained various experimental technologies (including even the prototype matter conversion machines[10]) in return for allowing Big MT to use the Sierra Madre as a proving grounds,[11] a decision that backfired catastrophically when the experimental technologies turned on the casino inhabitants, dooming them. Such an event was not unprecedented either, as the town of Hopeville was wiped off the map by a disastrous meteorological experiment in another such exchange, and later became the Divide.

The scientists' cooperation wasn't entirely frictionless. During one particularly heated dispute with Doctor Mobius, Doctor Klein threw the Sink's personality chips off the dome's balcony. The Big MT staff picked up the various holotape chips and stored them in existing facilities, and that of the Sink Central Intelligence Unit was personally recovered by the future Doctor Klein.

The Great War and its aftermath

When the Great War came, it did not stop the research efforts; it merely put them on a different rail. Mobius worked on predicting the post-holocaust economic systems. A new project was also started, with the purpose of preserving the Big MT "Think Tank" executives by transforming them into a special brain bot named after their group, allowing them to continue their work at Big MT indefinitely. With no one to stand in the way, their research continued, becoming more sinister and debauched as the years went by.

Eventually, the remaining human staff dispersed into the wasteland or were killed off by increasingly out-of-control experiments; like the escape of the cazadores and night stalkers. Only the six think tanks remained in the Big MT. Mobius, tired of the think tank's endless and horrible experimentation, thinking that "the world isn't ready for that kind of too-far-thing-taking" or believing his fellow scientists had finally lost what remained of their humanity, erected a radar fence - a kind of radar-guided repulsive field - around the perimeter of Big MT to prevent the disembodied brains from escaping into the wasteland, and destroying what little remained of humanity with his colleagues' planned experimentation on a new "fertile testing ground."

After a severe dispute with Klein, Mobius hacked his colleagues' shells, causing them to forget large portions of their personality and substituting their name with a new one, reinforcing the recursion loop already programmed before. Furthermore, he hacked the databanks of his colleagues, reprogramming their chronometers, geometers and cartography programs, essentially erasing their sense of time and history. He also forged several facts to focus the Think Tank's attention on himself: that his robo-scorpions consume intelligence from brains (creating the fear to go outside the central Big MT's dome), that he was exiled for crimes too heinous to remain in recorded memory, and a belief that Big MT is all that remains of the world, that nothing exists outside. In the end, his tampering created mangled, disjointed versions of his former colleagues. Disgusted by his actions against his friends, he erased some parts of his own memory to ease his conscience, such as this event (though not permanently, as certain phrases could reawaken the memories) and knowledge of his pre-War creation, the robo-scorpion.

Soon after, Mobius removed himself to the X-42 robo-warfare facility (renamed the "Forbidden Zone"), where he began to "re-create" the robo-scorpion, inspired by radscorpions wandering into Big MT. His new creation retained all features of the pre-War model: a tail-mounted energy bolt blaster, eyes systems allowing him to see through them, remote control and public address systems allowing him to monitor the Big MT. Fearing that the radar fence would not be sufficient to hold the mad scientists inside the crater, he set up a repeating threat message to be broadcasted to the Think Tank. The aim was to instill fear and prompt them to focus on retrieving technologies that would allow them to depose Mobius. When Big MT finally fell silent, it became the arena of an increasingly demented, insane struggle between Mobius and the Think Tank. The latter remained inside the dome, ever fearful of their self-appointed warden and his scorpions.

Big MT had few visitors, the sheer size of the crater serving as its best camouflage: most wastelanders assumed the ragged edges to be remnants of a massive nuclear explosion and avoided it altogether. The unfortunate few who wandered in disappeared forever, apprehended by robots and lobotomized by the think tanks to act as organic automata, maintaining the decaying facility or protecting it against scavengers.

Over the years, it became known in the wasteland as the "Big Empty," a place where nothing exists. Its size and aura of mystery blocked the establishment of trade routes and reliable supply caravans between the Boneyard and New Vegas, a fact that proved crucial for the survival of Caesar's Legion immediately following the First Battle of Hoover Dam, as the NCR was unable to reinforce its army quickly enough.[12]

The Visitors

Even though the facility's security was almost perfect, three people were able to elude the think tanks and survive the horrors intended for them, before the Courier arrived: Elijah, Ulysses and Christine Royce.

Elijah came to the Big Empty in search of weapons that would allow him to destroy the NCR and everyone who would oppose him in the creation of a new Brotherhood of Steel order. Elijah scoured the facility for technologies that would be of use to him in his endeavor. Namely, after learning of the Sierra Madre from Ulysses, he started gathering equipment that would allow him to crack the casino. The most important and sinister of these were the concentration camp detainment collars, that he experimented with during his stay.[13] He also took an unusable holorifle prototype,[14] perfected afterwards thanks to the holograms of the Sierra Madre.[15]

Ulysses came to Big MT by accident, having been following weather patterns from the Divide, recognising that storms that violent were man made, not natural.[16] Christine Royce pursued Elijah, tasked with killing him for the crimes committed against the Brotherhood of Steel.

Of the three, Christine was the only one who did not escape unscathed. Captured by Big MT robots following a disastrous skirmish at Little Yangtze and pitted against Elijah who sent the survivors of Little Yangtze against her like walking bombs, she was subjected to horrific experiments in the Y-17 medical facility conducted by some Mister Orderly and Y-17 trauma override harnesses and with a Mark IX Auto-Doc. These experiments permanently damaged her brain, destroying her ability to read and write fluently. She was saved from certain death by Ulysses, who destroyed the entities and nursed her back to health in his camp in Big MT. Afterward, he talked to her about philosophy and his desire to go into the central dome and speak with the Think Tank.

At some point, Elijah spoke with the Think Tank, which caused the Think Tank doctors to begin questioning their ideas regarding the world. The Think Tank began to doubt that their world was as small as they had perceived, bringing new ideas to their minds. After Ulysses and Elijah made contact, at which point Ulysses directed him to the Sierra Madre, Ulysses too spoke with the Think Tank, particularly Dr. Klein, who asked a lot about history. Ulysses asked a dangerous question: "Who are you, that do not know your history?" After Ulysses showed them the Old World flag, the Think Tank eventually remembered many past events, especially that there is a world outside the Big Empty, a world with ideas and possibilities for experimentation. Dr. Klein regarded the question as too dangerous, and, as it reminded him of too many past events, he subsequently deleted it from his memory. After coaxing the answers he wanted out, Ulysses returned to his camp to say farewell and pass on information to Christine about Elijah, and he left Big MT to travel onward to the Divide.

Elijah was the only one who left the Think Tank a parting gift. After being apprehended by Dr. 0 and Dr. 8, he hacked them both within minutes, permanently damaging 8's voice module and leaving destruction in his wake. He left Big MT on a cargo train, and then crashed the remaining trains in tunnels leading out of the facility. During these events, Mobius observed, even the conversation of Ulysses and Elijah with the Think Tank, rendered the inability to act on anything, and his fears grew surrounding the future actions of the Think Tank.

Sometime after the three left permanently, the Think Tank installed a pacification field in the Think Tank central area, preventing anyone without a brain to have hostile impulses. Afterward, to see if there really was something outside of Big MT, they sent a satellite prototype with a unique charge of teleportation outside of Big MT which crashed in the Mojave Drive-in in the Mojave Wasteland. It emitted a signal in the form of a jazz theme named mysterious broadcast that led to it. The Courier arrived, just after having been guided by the signal, inspected the satellite during the night and triggered the unique teleporter onboard the satellite, transporting themself to the Big MT.

Afterward, the Courier was taken to the Sink in preparation to become a lobotomite; but due to the gunshot wound from Benny causing a cranial injury in just the right place, it was enough for the Sink Auto-Doc to change its programming to fix the problem, improving the cranial extraction procedure. However, in the process, it was necessary to replace the spine and heart with synthetic organs. With the Courier's brain procedural data, the Think Tank would be granted the knowledge to modify their cranial selves into hosts to slip past the radar fence and leave Big MT. However, after the Think Tank extracted it, they degraded into bickering amongst themselves. Mobius saw an opportunity to steal the Courier's brain with its knowledge and led it into the "Forbidden Zone." Wanting to escape with the brain intact, the Courier was obliged to help the Think Tank against Mobius by retrieving three pieces of technology, changing the future of Big MT forever.


Big MT is dominated by the central dome named the Think Tank, which is connected to outlying facilities by numerous walkways, pipes, and conduits.

To the north lies the rail line that passes into Big MT via the Big MT north tunnel before splitting into two lines that run toward the east and west tunnels. Near the north tunnel is the X-42 robo-warfare facility, an important facility even with a dome; later known as the "Forbidden Zone," the lair of Dr. Mobius. Other notable facilities include the Signal Hills transmitter, the Saturnite alloy research facility, the X-22 botanical garden, and the X-17 meteorological station. Just north of the western train tunnel is the Little Yangtze concentration camp and the construction site.

To the east, along the eastern rail spur, lie several notable facilities, including the X-8 research center, the X-7b "Boom Town" target zone, the Securitron de-construction plant, the hazmat testing ground, and the waste disintegration platform.

The western portion of the crater is dominated by the X-66 Hexcrete archipelago, a collection of hexagonal concrete structures that vary in size from small platforms to towering monoliths. Among the hexcrete structures are several facilities, including the X-13 testing facility, the Z-43 innovative toxins plant, the Z-38 lightwave dynamics research building, and the X-7a "Left Field" artillery launch.

In the southern portion of the crater is Higgs Village, which contains the former homes of the Think Tank within a large, hangar-like structure. It is flanked by the X-12 research center and Y-17 medical facility.

This is not an exhaustive list of locations within Big MT, but notes some prominent facilities visible from the balcony of the Sink, Dr. Mobius's former apartment, located atop the central dome. For a complete list of locations, see Locations in Old World Blues.

Force field restricted locations


Originally meant as a beacon of new hope for humanity, Big MT eventually created a vast number of horrifying, unique creatures and machines, several of whom have made the Mojave Wasteland their home and killing grounds. Big MT's "legacy" includes:

  • Cazadores - hybrid insect creations of Dr. Borous that broke out of the facility.
  • Night stalkers - rattlesnake/coyote hybrid creatures, also created by Dr. Borous, that broke out of the facility and developed the ability to reproduce, despite their creator's assurances of sterility.
  • Spore carriers - human victims mutated by plant pollen, the same ones that infected Vault 22.
  • Lobotomites - countless lobotomized victims of Big MT's experiments.
  • Y-17 trauma override harnesses - robotic suits encasing long-dead bodies they were designed to save.
  • Robo-scorpions - Robotic guardians inspired by scorpions, created by Dr. Mobius.


  • While Dr. Borous states that he created cazadores in 2003, he is not a reliable source, as Mobius altered his chronometer, among other things.
  • Though many of the pipes crisscrossing the Big Empty can be used to traverse the area by walking on top of them to avoid some enemy attacks, some parts are also booby-trapped with frag mines.
  • Unlike in the Mojave Wasteland and Zion Valley, all enemy creatures and characters in Big MT are part of the same faction, and will not attack each other. The only exception to this is robo-scorpions, which upon losing sight of the player character (hidden) will fight with all other Big MT creatures and lobotomites until only the scorpions or the creatures/lobotomites remain.
  • Venturing beyond the perimeter of Big MT will result in a warning. Staying beyond the perimeter will result in being automatically teleported back to the Sink balcony. This happens even when over-encumbered with no penalty incurred and no health damage. It comes with the added benefit of furthering the Outer Space challenge.
  • It is mentioned by Joshua Graham, and later Ulysses, that Big MT is located somewhere near the Divide. Based on what Joshua Graham says, it is located somewhere near California State Route 127, across the Nevada border.
  • According to the Y-0 research center terminal entries, Big MT is south of Hopeville.
  • The only three radio stations that can be listened to in Big MT are the mysterious broadcast, the Happy Trails Expedition Broadcast, and the Sierra Madre Broadcast; all others are blacked out. These are the three add-on radio stations.


The Big Empty is mentioned in the Fallout: New Vegas add-ons Dead Money, Honest Hearts, and Lonesome Road and appears in the add-on Old World Blues.

Behind the scenes



  1. Old World Blues endings
  2. Third Street Municipal Building terminal entries; Office of the Treasurer terminal, Memo from Commander Devlin
  3. Y-0 research center terminal entries; terminal, Dispenser Funding Update
  4. The Courier: "Can you tell me about this facility?"
    Doctor 0: "*Big MT used to be a mountain. Then there was a... slight mishap. Now it's a crater - the Dome used to be buried, now it's exposed to the sky.* *Don't get me wrong. Makes the sky light up like a planetarium at night. All those spectra... so soothing.*"
    (0's dialogue)
  5. Old World Blues intro: "In the years before the Great War, Big Mountain had been the home to the brightest minds of the 21st century. Scientists of vision were drawn to the facility to tackle the greatest technological challenges of the era. They sought to create a new world, fueled by technology, for the benefit of all mankind. Sonic emitters, space age alloys, DNA hybridization, force field particle research, Auto-Doc advances in cranial, cardiac, and trauma surgery... ...the hopes and dreams of a century became realities in the electronic forges of Big Mountain. The nucleus of this research was the Dome, a huge stone facility that held the labs of every science known to man. It was a think tank where no problem could not be solved, where no question could not be answered. The Great War brought a new energy to Big Mountain and its scientists. Although sheltered from the frontlines, the scientists waged their own war, fighting their battles at the atomic level. Equations and calculations marched endlessly across chalkboards and computer terminals toward one solution: Winning the war. For years, the minds and computers of Big Mountain were a blaze of trajectories, weapon schematics, and nuclear theories. The problems began to outpace the solutions, first geometrically, then exponentially. As the war escalated, so did the questions."
    (Mobius' dialogue)
  6. Little Yangtze terminal entries; Little Yangtze log terminal
  7. X-8 research center teminal entries; terminal, Project: Burke and Project:Hare
  8. Doctor Mobius: "Klein... remember the time you forgot to carry the 2 and nearly blew up the Y-0 Research Center? Oh, wait, you did! Or was that me?"
    (Doctor Mobius' dialogue) Note: This is a randomized radio announcement.
  9. The Courier: "Sounds like you forgot your master plan - surprised you remember your own name."
    Doctor Mobius: "This name's as real as you or I, although I believe your brain expressed similar incredulity at the nature of such an appellation. Someone's been watching too many Old World science fiction movies, it said. I believe it meant me. I must admit I have a vulnerability for holotape fantasies of planets and robots and all that is forbidden. As for the name I was born with... ...like the Think Tank, we were all reprogrammed to forget them, take on new names. It enforces the recursion loop in our perception programming."
    (Doctor Mobius' dialogue)
  10. Y-0 research center terminal entries; terminal: Requisition Order: Dispensers
  11. Y-17 medical facility terminal entries; terminal: Sierra Madre: Test Case?
  12. The Courier: "The Divide blocked all of their northern land routes?"
    Joshua Graham: "Not all of them. But they couldn't take 127 north to get around the mountains. As if Death Valley weren't enough, they had the Divide and Big Empty to deal with. From what the Legion's explorers reported, the Big Empty may as well have been a wall to any living thing approaching it."
    (Joshua Graham's dialogue)
  13. Camp survivors and watch tower
  14. The Courier: "I've never heard of the place you're talking about."
    Elijah: "Big Empty's a treasure box, a scientific graveyard of Old World misery. Like the Sierra Madre... there's treasures there, sleeping. Some, awake. The Holorifle, the Saturnite alloy... the hologram technology, hibernation chambers, Securitrons, the collars... ...even the suits attached to those things stalking the Villa... that's only the surface of what's there. Right now, the Sierra Madre is what I want."
    (Elijah's dialogue)
  15. The Courier: "What is this rifle?"
    Elijah: "It is a Holorifle, a weapon I constructed when I arrived... I have since made superior models - and modifications. For now, that tool will have to do until you find other weapons... and I suggest you do, the Holorifle's ammo is limited. Still, it should serve well enough. I fashioned it from the Holograms of the Villa and used it against the Villa's... living inhabitants."
    (Elijah's dialogue)
  16. Ulysses' logs


  1. 1.0 1.1 PRACTICE 2015: Chris Avellone: "... So a lot of the work I had done for Boulder, Colorado in Van Buren had actually ended up mutating and actually becoming a part of the work that ended up being in Old World Blues, which was the Big Empty Research Facility, had a lot to do with the Boulder Dome that was in Van Buren."
  2. Big Empty concept art
  3. Blackfoot Tribe design document, p. 88
  4. Mesa Verde design document, pp. 9, 13, 21
  5. Reservation design document, pp. 36, 60-61
  6. Bloomfield Space Center design document, pp. 2, 3, 8, 17, 52
  7. B.O.M.B.-001 design document, p. 9