NEAR KIMBALL, Neb. -- Don and Charlene Zwonitzer are just a normal American couple. They like to garden.

"I love my greenhouse," said Char as she watered her basil plants.

They watch TV.

"Our big screen TV is our virtual window," said Don with a smile.

They conserve energy.

"We spend around the order of $130 a month in electric," said Don.

It just so happens they live behind a 47-ton blast door inside an intercontinental ballistic missile site.

"We're not crazy!" said Char. "We're not crazy at all. We just are unique."

Their unique way of life led them to the solitary plains of Nebraska, underground, to what's been called the ultimate fixer-upper.

"Our concrete roof is 2 feet thick. Then, we have 5 feet of dirt over that," said Char.

In the 1960s, at the height of the Cold War, the U.S. government used missiles as a deterrent. They placed hundred in hardened underground launch sites all over the country.

"This missile site was designed to withstand a one-megaton blast 1.6 miles away," said Don.

But after spending millions on each site, the military moved on.

Just two-and-a-half years after the Zwonitzer's site was up and running, it was rendered obsolete by missiles that could be activated more quickly, and the missile inside was removed.

In 1996, the Zwonitzers purchased the abandoned piece of history -- 20,000 square feet in all -- for the bargain basement price of $40,000.

Their home video showed a dilapidated, graffiti-filled mess.

"It was a dungeon," said Char. "It took nine months just to clean out this building of all the dirt and junk that was left in here."

But after 14 years, and a total of about $400,000, Don and Char have made their missile launch site into a home.

"We really love the place. It's comfy, cozy and really secure," said Don.

"At first, it was just going to be a functional, self-sufficient type of place," said Char. "But then I thought, 'If I'm going to live here, I want it to be homey and comfortable.'"

Char, trained in interior design, has thought of everything.

From hidden closets to an "outside underground," a giant room that boasts a functioning waterfall, pool table, ping pong and a hot tub.

Because there are no windows, they painted the walls white to make it bright.

"And I made blue carpet. So the sky is actually underneath us instead of above us," said Char.

The launch site is now Don's garage, and the flame pit has been converted into Char's greenhouse.

But don't let the transformation fool you, the place is still an underground fortress.

"I wanted to become self-sufficient, self-contained and self-reliant," said Don.

The Zwonitzers believe in being prepared for anything.

Don, a retired electrical engineer, has installed a state-of-the-art security system.

If the electricity goes out, they have battery back-ups and generators.

If they ever needed to, they have the food and supplies to live in the site with their children and grandchildren for at least a year.

Their one vulnerability: everyone knows about them. They've opened their missile mansion to hundreds for school tours and interviews through the years.

"Come in here and enjoy it. Learn a little about what we've done. Think about what we've done. Think about how you can apply it in your life," said Don.

To them, it's just common sense.

After all, they are just a normal American couple.

Additional Information:

Some of these abandoned missile sites are now data and document storage facilities. Others are research centers. One has even been converted into a high school.

To see the listing for a silo for sale outside Denver go to MissileBases.com. There, you could also read the history of there underground fortresses.