Remnants of a storybook amusement park hidden behind a strip mall.

This four-story steel sphere in Maryland was used to test biological weapons.

A historic cemetery filled with quirky faux wood art and unique tombstones.

The U.S. government built the million-pound stack of steel during the Space Race.

A relic of FDR's brief foray into utopian urban planning.

This golfball sized platinum iridium cylinder is the official starting point for all national weight calibrations

A mammoth pair of Civil War artillery guns abandoned out in the forest.

The development and impact of electronic media showcased in a picturesque farmhouse in Maryland.

A star fort along the C&O Canal in western Maryland that protected America in three wars.

The whole world in one water tank.

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

Rediscovered after a century, the father of the American Navy was reinterred in something dredged up from Davy Jones' Locker.

A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

This former asylum for Black Americans is haunted by its history of violence and racism.

A remote horde of architectural treasures fit for Indiana Jones.

Built by the patriotic residents of Boonsboro in a single day.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

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

A priceless collection of the Nation's cryptologic history.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.