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

Possible relics of the ancient Roman city are hidden in this restaurant's façade.

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

Where now stands a 42-story condominium tower of marble, glass and steel was once the central market of New York’s slave trade.

Unrepaired walls from a 1920 anarchist bomb attack.

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

This Fifth Avenue church has long been the favored worshiping place of Broadway actors and vaudeville performers.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

The one-time epicenter of American songwriting is now a little remembered Manhattan commercial block.

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

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

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

A Yiddish theater turned movie house turned rock and roll landmark turned gay disco turned bank.

A hidden "place of interment for gentlemen."

The greatest real estate coup of all time.

The iconic Manhattan corner that was once the site of the Beastie Boys' fake clothing store.

The competition: breathe deeply as long as you can.

The best place in New York to pick up the controversial, notoriously foul-smelling Asian "king of fruits."

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

Avoid gangster interaction while window-shopping.

This humble historic facade hides a history of boozing and the gentlemanly sport of rat-fighting.

Revolutionary War casualties fill the only 17th century structure remaining in Manhattan.