Two New York rooftops are home to the largest rooftop soil farms in the world.

There’s a secret bunker inside the Brooklyn Bridge, but the city won’t say where.

One of the last full-orchestra recording studios in New York City and an acoustical marvel.

This abandoned seaside fortress is now simply an imposing ruin being taken back by nature.

The home of aviation trailblazers, in a remote corner of the big city.

No monkeying around, this fountain was really named after the classic sci-fi film.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.

In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

You can still ride this 100-year-old work of art in Brooklyn's largest public park.

Volunteer-run library dedicated to exploring five decades of activism history.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

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

Visit the monolithic tomb of America's most famous general.

“Invented in Key West, Perfected in Brooklyn."

This innocent-looking townhome is actually a subway exit.

Deep under Manhattan is the largest construction project in city history. So far, the project has taken the lives of 23 workers, or "a man a mile."

Hordes of precariously balanced stone figures crowd the shores of the Hudson River.

The fanciest public restroom in New York City boasts fresh flowers, art, and a classical music soundtrack.

The last slot car racing arcade in Brooklyn is keeping the dream of speedy little autos alive.

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

This semi-hidden Manhattan restaurant is based out of a loading dock.

The oldest bibliophilia club in America, with exhibitions on historic books and graphic arts.

Nikola Tesla's former home contains an homage hidden from plain sight.

Bowl in splendor, if you're lucky.