Since Bethesda took over the Fallout franchise for 2008's third installment, the series has become even more popular over the years, though 76 proved to be a disaster at the time of launch. While some prefer the more classic, isometric PC titles, the fact that Fallout Shelter is the highest-selling Bethesda game shows that it thrives in the mainstream. One thing that perhaps helps keep the games in the limelight is the dedicated modding community. With it being made and published by Bethesda, it opens up the world to all kinds of custom content, including some which is reminiscent of other IPs.

Although known for taking place almost entirely above ground, in a desolate wasteland, someone has managed to create a more underwater environment for Fallout 4. Called "20 Leagues Under the Sea," this mod is essentially a new vault, Vault 120, that's been built in the sea. Created by MinitelRouge, this add-on seems to combine the post-apocalyptic settlements of the open world RPG with something that wouldn't go amiss in the first BioShock entry.

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Images show the detailed underwater environment, with corridors that look out into the vast body of water that buries the vault, and rising towers that even have some of the art deco aesthetic that greets players during the opening sequence of the first BioShock game. The description says that Vault 120 was built centuries ago in which people wished to escape the "madness of men up on the surface," again in a similar vain to the title that inspired this mod. There are also two settlements as well as a couple of workbenches.

Image from a Fallout 4 mod showing a Power Armor suit in a dingy red-lit vault.

For anyone who downloads the mod, the location of the underwater vault can be found to the northeast of Nordhagen Beach, seemingly on the way to Fallout 4's pirate utopia Libertalia. Aside from some irradiated creatures and space to create a community, there's not much else that's said about the add-on, so it's likely up to players to give it a go and see what's down there.

Like any good Bethesda game, Fallout 4 has a ton of community-made mods available to download. Some tweak the game in numerous ways to improve on the vanilla format, others fix bugs, while some implement new content entirely. MinitelRouge's "20 Leagues Under the Sea" falls into the latter category, and it's not just a standard mod, either. This will likely be one for both Fallout and BioShock fans to try out.

Fallout 4 is available on PC, PS4, and Xbox One.

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Source: Nexus Mods