A huge musical instrument played by the ocean.

The ruins of a fairytale castle with a tumultuous history stand high atop the mountains.

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.

This now-deactivated naval base defended the Florida coast for centuries.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

For thousands of years, Native American hunters drove buffalo straight off this cliff in Montana's Yellowstone Country.

The oldest badlands in North America, Makoshika State Park takes it name from the Lakota words for broken land.

This giant meditative chakra sits peacefully in the Flathead Valley of western Montana.

The rocks of a certain area of Butte, Montana give off a musical ring when hit.

Mining town from the late 1890s, once home to Calamity Jane.

This local gem houses the largest collection of pre-Raphaelite paintings outside of the U.K.

The highest point in Delaware is located under a trailer so this marker across the street will have to do.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

A blend of art, antiquities, and Americana fill this museum, surrounded by whimsical, enchanting gardens.

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

The highest point in Indiana is curated by an Eagle scout but may be in danger of losing its record to a nearby garbage pile.

A singular collection of hand-built art deco cars are held in a building with style to match.

You thought Santa Claus didn't exist, but it turns out you were wrong.

The farm where one of America's greatest leaders was raised is now a well-appointed landmark.

This elaborate estate contains a stunning marble aviary, a sunken conservatory, and a magnificent music room with a two-story pipe organ.

This unassuming home was once “grand central station” for the Underground Railroad.

The evolution of recreational vehicles and motorhomes is on display in the “RV capital of the world."

Modeled after the labyrinth in Chartres Cathedral, this small-town Indiana memorial labyrinth sits half a world away.

The body of one of the world's most famous outlaws is covered in cement and iron to prevent it from being stolen.