Harlem park dedicated to compulsive hoarders killed by their own junk.

Phil Mortillaro uses keys to bring art back to the Village.

A posh members-only club with a literally dramatic history.

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

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

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

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

The oldest house in Manhattan is now a museum that remembers the home's sordid history of scandals, vice-presidents, and ghosts.

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

Wine bottle sculpture with a ship's stateroom inside.

A very classy 1920s-era bar right in Grand Central Station.

Cryptic messages embedded in the New York City sidewalk.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

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

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

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

A semi-scholarly approach to sex.

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.

Elevated freight railway turned wildly successful urban park.

New York's unstoppable progress turned this cemetery into the smallest burial ground in the city.