This mysterious, medieval cathedral remains unbuilt but fiercely protected.

This Tennessee manse was built so opulent that the very utilities doomed it to fail.

This structure among the trees was the result of divine inspiration.

The longest-serving U.S. Secretary of State and Nobel Peace Prize winner was born in this humble cabin.

The pan man stands as a testament to the functionality of American cast iron cookware.

A heartwarming message to those entering and departing Music City from above.

This mansion turned restaurant was once a pitstop for Al Capone during his travels.

This church houses the “incorrupt” body of its founding Bishop.

This popular park is home to a sea serpent sculpture that now overshadows the twisted history of its creation.

This museum pays tribute to the Cherokee leader who created a written language for his people.

This limestone outcropping was once a ceremonial site for ancient Native Americans.

One man has spent decades faithfully constructing this unique brick and cinderblock castle.

This tiny 19th-century tunnel was built so a man could move his cows from one field to another.

This defunct, fortress-like prison has been the setting for several movies.

This quirky local sculpture is quite literally a fish out of water.

This Tennessee museum is dedicated to a tragic railroad hero who inspired the famous ballad that bears his name.

This museum dedicated to an oft-overlooked support industry features a surprisingly moving brass diorama of a man being saved from a sinking car.

This park contains one of the largest concentrations of cedar glades, a unique and rare ecosystem.

A key producer of charcoal iron in the early 1800s, the structure still stands today.

This large cave is a summer home to thousands of bats and has a rich history dating back to prehistoric times.

Hiding behind a grocery store is a spectacular cavern carved as part of an old limestone quarry.

The world's largest collection of porcelain "veilleuses-theiere," or night light teapots, includes four that belonged to Napoleon.

This simple, broken column marks the final resting place of one of America's most famous explorers.

An abandoned town is hidden in Great Smoky Mountains National Park.