The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

These old doors are covered in the signatures of Rehoboth Beach artists dating back to the 1930s.

The land is home to swimming ponies and a legendary 18th-century treasure.

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

Giant busts of 42 U.S. presidents are sitting in a field in Virginia.

A derelict bit of transportation infrastructure hidden in the woods.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

A wondrous old library overlooking the nation's capital.

A historic neighborhood church is reborn as a psychedelic arts collective.

This grand gothic brewery has been pumping out suds for over a hundred years.

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

People escaping slavery may have hidden inside a corpse vault.

Town of spiritualists and mediums in Florida.

Gutted airplanes slowly decay in a Florida field.

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

Disney's abandoned animal island is now an overgrown ruin that was almost the coolest attraction ever.

St Bernard de Clairvaux Episcopal Church, better known as one of the oldest European buildings in the Western Hemisphere.

Stay in a room with a view... of the bottom of the ocean.

A haunted hill that supposedly defied gravity.

Once featuring over 60 miniature replicas of famous Chinese locations, the Splendid China theme park was completely abandoned and is now mostly rubble.