The longest navigable underground river in the United States is home to countless blind and albino animals.

A historic hotel library in Indiana hides more than a few secrets on its shelves.

This huge clock made of flowers and simple machinery was once used a political weapon.

This grave marks the final resting place of a legendary frontiersman... unless it doesn't.

This stunning home looks like it belongs in medieval Europe, not North Carolina.

This Rocky Mountain mansion was the luxurious home of the authoritarian leader of a company town.

This tombstone marks the final resting place of the beloved 1990's character, Ernest P. Worrell.

Unique tower has outlasted a takeover of the company.

A pharmacy built in the shape of a mortar and pestle, now resembles a fancy cocktail.

This modern castle sat empty for decades before a fire inspired its builders to complete its luxury halls.

A monument to the center of the North American continent may be off by a few miles.

A monument celebrating the idea of reaching inaccessible places.

The center of the only hemisphere that awards visitors with a commemorative coin.

In this case, 'zero' marks the spot where the iconic Old Spanish Trail ends.

Arrr! The most authentic collection of pirate artifacts in the world... matey.

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

This shrine commemorates the site of the first known Catholic mass in the United States.

This abstract roadside poultry was saved from demolition by outraged drivers and pilots.

The ruins of a paper mill destroyed during the Civil War still tower over a tributary of the Chattahoochee River.

The statues commemorate the legendary mass killing of escaped circus monkeys.

A man's home is his castle.

A large boulder marks the place where the island of Manhattan was purportedly "sold" to the Dutch.

It's said that this stone with its mysterious runic inscription is evidence of the Norse visiting Narragansett.

A scenic ravine with an astounding collection of rock art created by the Indigenous people of the Great Plains.