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

This 220-year-old house is a reminder of New York City's Dutch past.

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

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

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

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

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

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.

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

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

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

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

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

Only hotel where you can legally launder money.

Prone to disastrous fires, the city of San Francisco has the Guardian, a fireboat gifted by residents, to watch over them from the bay.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

Art in the form of a winding, man made crack in stone.

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

This bar named after the world's first mixed cocktail was home to one of New Orleans' most notorious politicians.

The solemn exterior conceals an opulent interior of this 17th century church.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.