Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

An institution dedicated to the towering buildings that make up skylines in New York City and around the world.

On the Hudson resides one of the largest clocks in the world.

This evocative New Jersey statue memoralizes the Polish victims of a Soviet massacre.

Now abandoned, the first public health hospital in the U.S. saw more than one million immigrants from around the world.

A hidden "place of interment for gentlemen."

Not to be confused with the iconic New York City skyscraper, this Chicago building is a vibrant hub for artists.

Once called the "Polish Gold Coast" it is an icon of the neighborhood that bears its same name.

The palatial McDonald's that inspired Wesley Willis.

This historic hotel invented the chocolate brownie.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

The prototype for all Nazi concentration camps.

The boulder on which Alexander Hamilton laid his head as he died can still be visited on the New Jersey coast.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

What happens here stays here – unless it affects the whole world.

The famous facade of Grand Central Terminal hides a regulation tennis court, and it's not the first one.

Red frames showcase remnants of one of New York's original subway stations.

The origins of midtown Manhattan's anachronistic wooden farmhouse remain a mystery.

During the 19th century, you could pay for violence off a prix fixe menu on this Manhattan street.

A grand New York post office that is home to mailman Santas, scraps of postal history, and a pneumatic mail system.

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