Since Russia invaded Ukraine in February, demand for nuclear shelters in Europe has skyrocketed, including higher-end units selling for as much as $8 million each.

"In the first few weeks of March people were really scared and wanted immediate help," Claus Haglund from Bühler GmbH, a Swiss firm that installs and repairs bunkers, told The Telegraph in an April 30 report. "Basically, they wanted to know how quickly their bunkers could be made useable."

Inquiries on units have dramatically increased in the past several months, and are continuing as Russian officials, including President Vladimir Putin, insinuate the possibility of using nuclear weapons in the conflict, CBS News reported in March.

"We've got a world superpower threatening to use nuclear weapons; that alone is enough to be scary," Texas-based Rising S Co. General Manager Gary Lynch told the news outlet regarding the rising number of people from Europe seeking information about his company's line of shelters.

Lynch said his company, which makes prefabricated bunkers and ships them all over the world, received 1,600 inquiries in a 10-day period, leading to 40 sales of between $60,000 and $200,000 each.

"Normally, in that same time frame I would have sold five," Lynch said, describing his new customers as "hardworking people who are taking the measures to protect their loved ones."

But it's not just your average people looking for protection, The Daily Mail reported in early March that prices for the units vary from $85,500 to more than $8 million each, sheltering as many as 45 people, and several vehicles in an underground garage.

In addition to living space, the units also provide filtered air systems that can eliminate biological or chemical weapons containing anthrax, sarin gas or mustard gas.

''Just look at what's going on. [Putin] is threatening nuclear war, saying it would be something the world has never seen,'' Lynch told the Daily Mail. ''The world has seen Hiroshima. And if what they are threatening is worse than that then, by all means, we should all be worried.''

Buried 11 feet underground, Lynch said his units can include ''grow rooms'' for food, fitness centers, swimming pools, firing ranges, bowling alleys and elevators.

''Don't make fun of or criticize people that have valid fears,'' Lynch said. ''They want nothing more than to protect their loved ones in a terrible, terrible time. The only way you can prepare yourself to fail is by not preparing.''

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