More than five miles of underground passageways.

Visit this playground of waterfalls, caves and sinkholes.

Better known as the "Body Farm," this unique research facility has been studying how human bodies break down since the 1980s.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

All that's left of the quintessential "cabin in the woods."

Home of an evil witch famous within southern folklore.

Enormous lake at the bottom of a unique cave system.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

This striking art museum holds an amazing series of curiosity cabinets.

Homemade outdoor church and sculpture garden decorated with glass shards.

Hidden away in the city of Madison, Wisconsin is a nearly forgotten home that Frank Lloyd Wright built for a childhood friend.

One of Frank Lloyd Wright's final works was this UFO church.

The spaceship-like theater, which is still in use, was one of the most popular exhibits at the 1964 New York World's Fair.

The only Frank Lloyd Wright-designed structure in the architect's hometown.

Six tiny houses built for working class people form the largest intentional cluster of Wright homes anywhere.

This odd-shaped relic from the 1964 New York World's Fair found its way back home to Wisconsin.

This supper-club-turned-concert-venue still serves drinks at its original rotating bar.

Wisconsin's most celebrated export gets the royal treatment on I-94.

This pebble beach is so beautiful that taking its rocks is against the law.

This cave holds a surprisingly colorful variety of geological oddities.

Robots, lasers, and whoopee cushions, oh my!

"World's largest scrap metal sculpture" stands in an outdoor sculpture garden in the middle of Wisconsin.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

"Looks so real, it's scary!"