Walk the whole Mississippi River!

This head-spinningly bizarre Depression-era art cave is wall-to-wall quartz and Jesus.

The secret city built by the Manhattan Project.

This replica of the Greek structure is in the heart of Nashville.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

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

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

Mile-long cave system near Great Smoky Mountains.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

Over 20,000 sets of spice shakers reveal the surprisingly telling history of our most basic spices.

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

One-layer pyramid in Indiana.

A modern-day wunderkammer dedicated to Indianapolis history, Afrofuturism, and musical vibrations.

This Indiana walk of fame honors music legends with record-shaped plaques in the pavement.

A collection of over 2000 air-moving devices of all kinds displayed in the Fanimation headquarters.

A giant concrete egg marks this Indiana town as the "Egg Basket of the Midwest."

This former Indiana quarry has been transformed into a park and SCUBA site where divers can explore the drowned mining equipment.

Colorful collection of antique musical oddities.

Down the road from where the Wright brothers lifted off is another flight tribute practically hidden from sight in the woods.

The humble horn finally finds a place in the sun.

The Cadillac Ranch for monster truck aficionados.

Every week, a festive public jam session breaks out in downtown Asheville.

A historic dam made famous for its turbines and feature in a Hollywood classic.

Practice your Dirty Dancing lifts in the manmade lake where Johnny Castle himself did.