The walls of America's oldest masonry fort famously "swallowed" cannonballs.

Possibly the world's oldest rug, this Egyptian relic is woven entirely from ancient cat hair and once carried a mummified human foot.

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

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

It's a pretty creepy lock-up.

Two men built this castle on the Florida coast as an artistic “landscape sculpture.”

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

A luxurious 1880s hotel with its fair share of Tiffany stained glass, Edison electricity, and of course, ghosts.

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

A blacklight journey through a celestial art exhibit.

A museum dedicated to the alleged Roswell Incident.

Once the most flame resistant building in the country, the South Carolina Historical Society building was almost burnt down in a fire.

This small memorial is almost as well concealed as Smalls himself was on the night he sailed to freedom.

Dedicated to the history of the health sciences.

A stack of stones steeped in Irish folklore, much like the hero they're connected to, hide in plain sight.

Oldest unrestored plantation house in America that is open to the public.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

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

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

Unique tower has outlasted a takeover of the company.

Three courses accompanied by Christian rock.

One of the greatest boxers and humanitarians to ever live chose his hometown as his final resting place.

The largest cemetery in Louisville is the final resting place of Col. Sanders and Muhammad Ali.