A commemorative plaque hides a door that leads down to the New York Public Library's underground book bunker.

A touching tribute to the "Queen of Soul."

A Manhattan office building is home to the world's largest chess board.

The most confusing clock in New York.

There must be a pun in this haystack somewhere...

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

A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

An artist's cute bronze subway sculptures belie his violent artistic past.

Deep under Manhattan is the largest construction project in city history. So far, the project has taken the lives of 23 workers, or "a man a mile."

Built as a gift to the hottest tastemaker of the time, these hidden quarters remain an Art Deco showpiece.

Lie in a hammock where George Washington stood.

A WWI fighter plane and turn-of-the-century penny candy shop are among the unexpected features of this Financial District building.

A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

Hordes of precariously balanced stone figures crowd the shores of the Hudson River.

A dark, dank room in subterranean Manhattan was the site of a ghastly murder.

One of the most enjoyable bits of history at Coney Island and “the most romantic ride in the world.”

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

The fanciest public restroom in New York City boasts fresh flowers, art, and a classical music soundtrack.

An unassuming secret door once led to a legendary watering hole.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.