A well-worn marker in a forgotten alleyway is all that remains of what had been one of Manhattan's most beautiful buildings.

A trove of century-old litho stones from the Puck Building's printing days were discovered behind a cellar wall, and are now hanging in the store.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

Magnificent New Deal Murals evoke a time when New York City harbor was one of the world's greatest and busiest ports.

This Upper East Side apartment co-op was designed as a tuberculosis sanitarium.

The home of the first American-born saint is one of the only curved buildings in New York.

An artist's cute bronze subway sculptures belie his violent artistic past.

Visit the site of a subway powered by nothing more than air--and lots of it.

Red frames showcase remnants of one of New York's original subway stations.

Plot your trip through the city on the sidewalk.

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

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

The last remnants of what was once one of the world's grandest hotels can now be found in a Manhattan subway station.

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

During the holidays, a vintage subway train whisks New Yorkers back in time.

Beautiful mosaics cover the first stations opened on New York City's newest subway line.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

Built as a gift to the hottest tastemaker of the time, these hidden quarters remain an Art Deco showpiece.

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

The famous facade of Grand Central Terminal hides a regulation tennis court, and it's not the first one.

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

A miniature rainforest is growing inside of a Midtown Manhattan office building.

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

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