The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

This bridge is haunted by the ghost of a distraught mother.

The Dover International Speedway is home to a towering, concrete-skinned, racecar-hungry behemoth.

A grotesque Fiji merman dwells within this traditional Dutch-style building.

A desiccated merman and a walrus penis bone are among the oddities in this eclectic collection of shipwreck treasures.

WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

The historic home still shows the scars from a little run-in with the British in 1813.

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

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

An eerie, decaying ghost town destined to fade into the forest.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

The trials and tribulations of marking Poe's grave.

Home of the physician who set the leg of John Wilkes Booth after the Lincoln assassination.

The remnants of a wooden-hulled fleet built and abandoned in WWI, now home to a thriving ecosystem.

On the Hudson resides one of the largest clocks in the world.

Memorial built in 1922 in remembrance of WWI casualties.

Step inside Lucy, the world's largest "elephant."

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

Yo, Adrian!

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

One street divides a single town that stands in two U.S. states.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

This free, take-a-book shop seems like a trick but isn't.