Fallout is built around the existence of vaults—pre-war bunkers constructed by the mysterious Vault-Tec corporation. However, it’s often shocking to learn that these vaults were never destined to actually save anyone, with only a tiny percentage of these seemingly safe havens being used to live out the nuclear apocalypse. In Fallout, Vault-Tec designed these bunkers with a range of experiments in mind, all of which fell within the confines of the Societal Preservation Program.
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What better way to perform experiments on unsuspecting members of the public than to lock them in an inescapable underground vault at the height of a nuclear war? With the Societal Preservation Program, Vault-Tec created all manner of tests and studies, from the scientific to the downright bizarre. In Fallout, very few vault dwellers were safe, and many entered their respective bunkers completely unaware that they were walking into a nightmare.
Updated on January 20, 2026, by Anastasia Maillot: Season 2 of Amazon’s Fallout continues to successfully spark interest in the franchise, with rumors of remasters of previous games and even some whispers of Fallout 5 floating around. While we don’t have anything concrete just yet, it’s time to jump back into some of Fallout’s Vault-Tec lore, given the abundance of new info we have from the TV show. This list will mostly focus on just plain weird experiments, rather than downright cruel ones, although a lot of these are still absolutely heinous, all things considered.
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Vault 21: A Gambler’s Heaven
Dice Rolls And Luck Were Conflict Resolution Methods
- Seen in: Fallout: New Vegas
- Location: Mojave Wasteland
Vault 21 is a little bit different from your typical vaults seen in the Fallout universe. Usually, it’s the same story: you find an abandoned vault that’s been repurposed, following the death of nearly everyone inside, and the failure of its impossible experiment. Vault 21 actually started off as a business on the Las Vegas Strip. It was a hotel first, and once the bombs fell, it served its second purpose as a vault, where the main point of the experiment was to solve all disagreements and conflicts with a game of dice or gambling.
Although you’d think something like that would inevitably result in chaos at some point as competitive players lost their cool, it reportedly did quite well, until Mr. House took charge of it (and, would you believe it, the decision as to whether or not he should be allowed to was resolved with Blackjack) and opened it up, thus ending the experiment. In New Vegas, parts of the Vault have been filled in with concrete, and some of it can be visited as it now functions as a hotel. That said, the initial concept for the experiment is definitely weird and quirky, and very much Vegas in every sense of the word.
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Vaults 31, 32, And 33: Bud Askin’s Weird Project
The Making Of A New Gen Of Vault-Tec Servants
- Seen in: Fallout TV show
- Location: Mojave Wasteland
The Fallout TV show introduced fans to a Three Vault system made between Vaults 31, 32, and 33. This was a pretty neat concept, considering most vaults up until now had always been in complete isolation from the world, and especially other vaults. In fact, most inhabitants had no idea there were different vaults out there with different purposes, unless they were high enough at Vault-Tec. The Three Vaults were part of a special program created by Bud Askins called Bud’s Buds.
The goal was to basically use the three vaults to breed a new group of Vault-Tec loyalists to carry on the company’s legacy even years after the world had ended. Vault 31’s purpose was to serve as the main source of propaganda, with some of Bud’s Buds’ best individuals preserved in cryosleep and regularly thawed out to ensure the creation of new loyalists in the two other Vaults. All the while, those in Vault 32 and 33 were under the impression that the system only existed to support one another. It’s dark, and it’s weird, in a dystopian corporate way that perfectly fits the Fallout universe.
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Vault 108: Gaaaaary
A Vauly Filled With Gary Clones
In Fallout 3, released in 2008, players stumble upon Vault 108, completely devoid of life except for a collection of clones, all named Gary. They’re an aggressive bunch, targeting the player from the moment they enter the vault, charging forth while crying out one word: “Gaaaary!”
If that wasn’t bad enough, the vault was left poorly staffed and badly organized from the start, with power systems being pre-arranged to fail after a twenty-year period. Following a string of medical experiments by the dwellers, a man named Gary was cloned over and over again, each time becoming more aggressive. Ultimately, it’s assumed that the Garys took over, as when the player arrives at Vault 108, all that remains is a collection of clones.
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Vault 75: The Vault In The School
The Vault That Separates Families
Fallout 4 introduced players to Vault 75, one of the most bizarre and horrifying vaults in the history of the franchise. Hidden under a school, Vault-Tec’s ruse was that this vault would give children and their families a safe place to hide out from the impending nuclear apocalypse. However, the truth about Vault 75 couldn’t have been more gruesome.
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As the player explores Vault 75, they learn that families were split up when they entered the vault, with the parents being executed while the children were led deeper into the bunker. Following the slaughter, the children were told that they were being made strong enough to face the horrors above ground. In truth, children who didn’t perform as expected were ‘harvested’, and those who were a shining example simply joined the scientific team studying the children.
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Vault 81: For Science
Sabotage From Within
In Fallout 4, the player will eventually find Vault 81, a unique vault in that it’s still perfectly operational, with many vault dwellers living safely inside. However, the survival of these vault dwellers is only due to the failure of the vault’s original experiment, which would have exposed the inhabitants to all manner of infectious diseases, while Vault-Tec scientists watched on from a parallel observation vault.
Fortunately, the first overseer of Vault 81, a Dr. Olivette, refused to toe the line, ultimately sabotaging the entire experiment. As the observation vault was totally hidden, the real inhabitants of Vault 81 had no idea how close they had come to certain death. Even if they had carried out the experiment successfully and the vault dwellers had tried to escape, they would have been brutally incinerated by the Vault-Tec observers.
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Vault 87: FEV Horrors
The Forced Evolutionary Virus Is Deadly
Vault 87 is a terrifying vault hidden deep within Fallout 3’s DC Wasteland. It’s the ‘birthplace’ of many of the region’s mutated creatures, from the Centaurs to the Super Mutants. As one of the most advanced Vault-Tec bunkers, Vault 87 was fully equipped to take control of the Forced Evolutionary Virus, using it to experiment on human and animal subjects. This virus was effectively responsible for the creation of some of the most iconic, horrifying creatures in the franchise.
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Unfortunately, the security systems within the vault failed after just one year, allowing the test subjects to escape from their holdings. They went on a rampage, with the Super Mutants bursting onto the surface and starting to kidnap as many explorers as possible, bringing them back to the vault to convert them into their kind. It’s an extremely tough vault to explore, and players who stumble upon it are often in for a nasty surprise.
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Vault 114: The Wealth Experiment
Nobody is Too Rich To Suffer
At first, Vault 114’s experiment might seem petty, but it’s certainly a contender for the most bizarre Vault in Fallout history. Located in the Boston Commonwealth in Fallout 4, Vault 114 was created to test the behavior of wealthy inhabitants after they’ve been stripped of their status and belongings. In Vault 114, only the richest, most elite members of society would be granted access, and when the bombs fell, they’d find themselves living in absolute poverty.
To make matters worse, Vault-Tec intended to put in place as strange and incompetent an overseer as possible. They ultimately settled on ‘Soup Can Harry’, an eccentric vagrant with a delusional mindset. Fortunately for Boston’s elite, Vault 114 never entered service, and when the player finds it hundreds of years later, it’s occupied by a gang and relatively unfinished.
5
Vaults 68 And 69: Outnumbered Inhabitants
Not A Good Ratio
Both Vault 68 and Vault 69 were cut content, stripped from showing up in Fallout 2, but are still documented. Had they been featured, they might have just taken the prize for being the most bizarre vaults in the Fallout franchise, boasting experiments that were unbelievably strange. In these vaults, there was a dramatic imbalance in the arrangement of the inhabitants that would have certainly caused countless issues.
In Vault 68, one thousand occupants would enter—999 men and one woman. In Vault 69, there would be 999 women and one man. While it isn’t known what happened in these near-conceptual vaults, it’s safe to assume that some horrible things may have taken place. Which vault was worse is up to the player’s own imagination.
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Vault 11: The Ultimate Sacrifice
Those Who Don’t Sacrifice, Don’t Survive
Vault 11 can be found in Fallout: New Vegas, and it’s a bunker that contains a bizarre, twisted, and heartbreaking backstory. From the moment the inhabitants entered the vault, they were told that every year, they’d have to select one of their fellow vault dwellers and execute them. If they didn’t, they were led to believe that the entire vault would be incinerated, killing everyone inside.
However, the truth was something tragic, as in actual fact, if the occupants refused to make a sacrifice, the door to the vault would unlock, and they’d all be allowed to leave. In the climax to this backstory, it’s revealed that the occupants were whittled down to the final five, at which time they decided to stop making sacrifices. At that point, four of the five survivors settle on ending their own lives, but the last, lone dweller refuses to give up, opting instead to leave the vault, never to be seen again.
3
Vault 92
The Sonic Experiment
Vault 92 can be found in the Capital Wasteland in Fallout 3. The whole purpose of this Vault was to find out if people could be controlled into committing acts of violence with the use of modulated ultra-low frequency white noise. Vault Tec’s plan was to use the noise to create Super Soldiers.
It didn’t take long for things to fall apart. One of the Vault’s musicians, Subject V920717, lost his mind and murdered three other Vault dwellers. He was only stopped when the security team shot him multiple times. After a while, the whole Vault fell into a state of disrepair after the maintenance crew died. It wasn’t long after this that parts of the Vault became flooded, and various mutated creatures took over.
