A small peaceful park and waterfall tucked amid the urban grind of Midtown Manhattan.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

Walk into the 19th century without leaving Brooklyn.

This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.

A six-story treehouse offers spectacular views of New York's Finger Lakes region.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

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

This small and serene place for quiet reflection on Staten Island was built in China based on the gardens of the Ming Dynasty.

This old cement mine has been used as everything from a mushroom farm to a recording studio.

What was once a trend-setting, phrase-coining icon of architectural splendor is now a rotting, forgotten hulk.

One man's swirling six-acre monument of stone.

Reclaimed by nature, the ruins of Doodletown, New York are remnants of a town consumed by a state park.

This abandoned seaside fortress is now simply an imposing ruin being taken back by nature.

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

Thriving meadows span a rooftop in one of Brooklyn's most heavily industrialized neighborhoods.

This plot of old-growth forest is the largest surviving remnant of New York City's original woodland.

The name of this tiny pocket park tucked between two buildings on Manhattan's Upper West Side is Latin for its location: "seventy-one."

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

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

A Victorian cemetery in the heart of Brooklyn remains a popular mecca of morbid curiosity.

In upstate New York, gorgeous waterfalls and a watermill are slowly being reclaimed by nature.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.