This little museum is built on a theater that was once a wildly elaborate speakeasy.

Tucked in the back of this amazing antique store is an important piece of medical history.

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

A hidden "place of interment for gentlemen."

A crumbling hospital from the 1850s on Roosevelt Island.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

One of only two commuter aerial tramways in the United States.

Site of the first pathological and bacteriological research facility in the United States.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Spinning silently in the lobby of an Art Deco masterwork is a massive vintage model of the Earth.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

Monument to a forgotten NYC disaster that claimed the lives of 1,000.

A unique sculpture park that specializes in the huge and bizarre.

On the top floor of an upscale department store stands a lavish restaurant housed in a replica of a luxury French dining car.

Behind a bodega is a small museum of relics and ephemera showcasing the history of New York.

This monument to a veteran of the Mexican-American War is one of only two in Manhattan that serve as an actual mausoleum.

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

Twice a day one of these tragic bronze mariners drowns with the tide to remember all those the sea has taken.

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

Currently housing a corporate bank branch this building at the southern tip of Manhattan was once the gateway to luxury vacationing.

Unrepaired walls from a 1920 anarchist bomb attack.

Built hundreds of years ago this downtown iron barrier once protected a much despised king.

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

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