Manhattan's Thirteenth Avenue was made on landfill then deliberately destroyed — apart from one small, obscure block.

New York City's smallest piece of private property.

Elevated freight railway turned wildly successful urban park.

A dilapidated dock tells the story of Titanic's missed arrival.

The only subway station in the city that still makes use of gap fillers.

The most confusing clock in New York.

This abandoned subway station can still be seen on regular commuter trips.

Twenty-three trees, each paired with a basalt stone, line a street in Chelsea, continuing an urban project started by German Fluxus artist Joseph Beuys.

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

Stunningly detailed mosaics in a New York subway station bring life to the Weimaraners of artist William Wegman's work—and to thousands of commutes.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

A semi-scholarly approach to sex.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Rat sculptures try to infiltrate the Graybar Building in an architectural tribute to New York City's nautical history.

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

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

A masterpiece of LGBT art has been restored in what may now be the most valuable restroom in America.

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

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

This study room in the New York Public Library saw the creation of one of contemporary America's greatest traitors.

One of the last few places in Manhattan that employed a pneumatic systemic keeps it on display.

A commemorative plaque hides a door that leads down to the New York Public Library's underground book bunker.

This private home is famous for appearing in the cult-classic "Twin Peaks" series.