Vivos has plans to add more amenities to the South Dakota site in the future, including a hot tub, spa and theatre for members to enjoy when it's safe to resurface.

Ultimately though, the company sees its underground communities as humanity's last chance.

"What it's about is the next generation. Providing them an opportunity to survive, to come out of the bunker someday, to look around and say, wow, we have another chance," says Vicino.

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