Hodge bought into the first of a proposed nationwide group of 20 fortified, underground shelters — the Vivos shelter network — that are intended to protect those inside for up to a year from catastrophes such as a nuclear attack, killer asteroids or tsunamis, according to the project's developers.

"It's an investment in life," says Hodge, a Teamsters union representative. "I want to make sure I have a place I can take me and my family if that worst-case scenario were to happen."

There are signs that underground shelters, almost-forgotten relics of the Cold War era, are making a comeback.

The Vivos network, which offers partial ownerships similar to a timeshare in underground shelter communities, is one of several ventures touting escape from a surface-level calamity.

Radius Engineering in Terrell, Texas, has built underground shelters for more than three decades, and business has never been better, says Walton McCarthy, company president.

The company sells fiberglass shelters that can accommodate 10 to 2,000 adults to live underground for one to five years with power, food, water and filtered air, McCarthy says.

The shelters range from $400,000 to a $41 million facility Radius built and installed underground that is suitable for 750 people, McCarthy says. He declined to disclose the client or location of the shelter.