These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.

World's first "penitentiary," meant to be humane, drove men insane.

An abandoned stretch of highway, deteriorating next to the operational one.

This abandoned Poconos resort is haunted by a history of kitschy romance and a violent fugitive.

This huge, disused viaduct is now a crumbling concrete underworld of covered in years of graffiti.

The graffitied ruins stand hidden within the Pennsylvania woods.

This semi-spooky remnant of an abandoned hotel provides fantastic views.

A crumbling hospital from the 1850s on Roosevelt Island.

Abandoned 19th century homes once occupied by naval officers, soon to be demolished.

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

From scholastic to sepulchral - now under reconstruction.

This once luxurious Catskills resort is now a haunting ruin.

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

A long abandoned hospital building on the outskirts of NYC.

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.

The remains of a failed subway in upstate New York is now an underground graffiti bunker.

This mouldering abandoned mental hospital was once a center for progressive healing.

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

An abandoned asylum once on the cutting edge of lobotomies may be reborn as a Christian college.

The abandoned ruins of America's first private zoo are open for exploration in the Catskills.

A forsaken wonder in the middle of the East Side neighborhood.

A mysterious, abandoned building rotting on the Brooklyn waterfront.

The remains of what was once the world's steepest passenger funicular.