Mysterious 500-year-old tapestries depict a unicorn hunt.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

A celebration of capitalism in Midtown.

Peek through the gates at this oasis from the city, full of Old English charm.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

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

New York City's smallest piece of private property.

A dilapidated dock tells the story of Titanic's missed arrival.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Elevated freight railway turned wildly successful urban park.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

Less a museum than a bizarre fantasy world created by artists and engineers.

Patrick Dougherty's fantastic living tree sculptures, mind-blowing but temporary.

Symbolic attempt to overcome the issues of life.

Part of a worldwide art project, this mysterious semicircle of concrete shapes holds the pieces of a larger story.

This open air cathedral invites all faiths to worship under the only roof big enough to fit them all: the sky.

Purdue students would lean over this iron fence to skirt campus rules against smoking and courting.

You thought Santa Claus didn't exist, but it turns out you were wrong.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

The body of one of the world's most famous outlaws is covered in cement and iron to prevent it from being stolen.

A flamboyantly decorated bridge signals diversity and fellowship at the entry to Indianapolis' Broad Ripple Village.