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

Home to the abandoned Tioronda Hat Works Factory, this park is a combination of woodlands and marshlands.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

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

Thirteen pastel palaces in downtown Charleston add a gorgeous splash of color to the city.

The abandoned coal loading dock is a canvas for unsanctioned art.

Where America’s first doomsday cult awaited the end of the world.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

This giant disembodied horse head seems to balance impossibly on its nose.

A giant scrap metal troll rests his hands on top of a dilapidated building covered in graffiti.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

The world’s first penitentiary, meant to be humane, drove men insane.

Run by a eugenics advocate, this aging institution conducted secret radiation experiments sponsored by Quaker Oats.

Unlike other abandoned asylums this empty institution welcomes visitors, just don't go in the buildings.

Ralph Waldo Emerson spent two years living here decades before it became a Frederick Law Olmsted-designed park.

The often-overlooked ruins of one of the first buildings designed by famous landscape architect Frederick Olmsted.

The bears may be gone, but their old cages can still be found.

The site of Paul Revere's historic two lantern warning.

Stunningly detailed mosaics in a New York subway station bring life to the Weimaraners of artist William Wegman's work—and to thousands of commutes.

This hidden oasis features a stunning view of the Hudson River and the Palisades from a castle-like museum.

The artist and New York City icon lived, worked and died in this converted carriage house owned by another iconic artist, Andy Warhol.

A deteriorating 1990s Girl Scout camp in a beautiful lush park on Lake Ontario.

Empty, but not abandoned, this cavernous Brooklyn loading dock was once considered the largest individual building in the world.

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