Toxic waste disaster that founded the Superfund program.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

An abandoned horticulture institute gloomily presides over rows of derelict and vine-wrought greenhouses.

A once grand hotel is being retaken by the wilderness it once capitalized on.

Once America's longest-manned military fort, now an abandoned hulk.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

This abandoned factory on the Hudson River once churned out a million bricks a week.

An abandoned asylum where patients have been forgotten but their possessions remain.

Hundreds of numbered stakes hidden in the woods mark the graves of the lost souls of a nearby asylum.

A forgotten relic from New York's bygone trolley system hides in plain sight under a bridge.

A retired subway car stands alone in a field in the middle of Queens.

This once sprawling resort now sits abandoned, filled with graffiti and vibrant colors from an era long passed.

"Gnome Chomsky" was once the largest gnome in the world, but is now simply tall for his kind.

An abandoned castle owned and ignored by Masons carries a cursed history.

A fictional town that was briefly brought to life before fading once again out of existence.

Pluto is still considered a planet in Ithaca, New York.

This peaceful gem in upstate New York was chosen as the future home of the 14th Dalai Lama's Library and Museum.

A gazebo that inspired the fifth episode of the "Twilight Zone" still stands in the creator's hometown

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

Famously misunderstood wonder of the ancient world