This otherwise innocuous bodega was once the headquarters of the most feared assassin's guild in American history.

Cryptic messages embedded in the New York City sidewalk.

New York City's only preserved family home from the 19th century.

A Victorian cemetery in the heart of Brooklyn remains a popular mecca of morbid curiosity.

A hidden "place of interment for gentlemen."

A charming "tea atelier" hidden away in Greenpoint, Brooklyn.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

Manhattan's lighthouse, erected at the insistence of the unsinkable Molly Brown.

This enormous Hindu temple in Queens serves incredible dosas in its basement canteen.

The first and only carousel with a lineup entirely of insects.

A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

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

The only home that Alexander Hamilton ever owned has a history almost as troubled as his own.

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

The famous author's cottage hideaway.

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

First a horse rendering plant, then a 19th century landfill, this beach is full of glass from thousands upon thousands of broken bottles.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

Tucked in a nondescript downtown Brooklyn mall is a bar containing a remarkable turn of the century anatomical wax collection last seen in 1920s Berlin.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

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.

A hip bar decorated with walls of golden skulls.