The world's longest known cave system.

The picturesque southern city served as the zombie-filled town of Woodbury in 'The Walking Dead.'

A historic freight system that found the true gold rush is in tourism.

A rare chance to get up close and personal with a 13-mile ribbon of ice near downtown Juneau.

Remarkably realistic Florida shoal bass "swim" inside this large globoid sculpture.

The only Florida state park with publicly accessible caves.

One of the only Florida forts to remain in the hands of the Union all through the Civil War still stands as a historic stronghold.

Town of spiritualists and mediums in Florida.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

Bad farming practices caused this unnatural natural wonder.

Megachurch turned Catholic church comprised of 10,000 glass panes.

This massive redwood tree has a hole in the base big enough to drive through.

Quite simply the largest tree in the world (by volume).

Costumed elves and mountain bikers co-exist peacefully at this abandoned Christmas-themed adventure park.

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

Just below the surface, shrimp are producing temperatures hotter than the sun.

Florida might be at its most surreal in this museum devoted to the famed Spanish artist.

The story of a Floridian city as told through an obscure sport for retirees.

A tribute to Ponce de Leon's supposed quest for eternal youth.

Intertwined, interspecies trees which locals believe can grant boons to lovers.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

An octet of classic chrome trailers speared into the ground act as a tribute to the silver bullets of the open road.

A building so large that it has its own weather.