The first AIDS memorial chapel in San Francisco and one of only a few in the U.S.

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

A morbid piece of memorabilia from the most famous shipwreck in current history is just one of the many poignant artifacts in this Canadian museum's collection.

Fascination continues to surround one of history's most infamous shipwrecks.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

The front yard of an Upper East Side town house hides the last fragment of one of New York's most famous theatres.

A famous songsmith's custom piano, dubbed "High Society," is hidden just out of sight in one of New York's finest hotels.

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

An annual extravaganza of Broadway theater memorabilia.

An overgrown garden stands as a grim marker of an unrealized dream.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Once considered the height of medical modernity, this structure is now the oldest remaining component of Roosevelt Hospital.

From this desk Al Hirschfeld drew his influential caricatures of the 20th century's Broadway stars.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

The loneliest island in New York.

Small monoliths of several varieties of stone sit alongside a wooded path in the Bronx.

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

This Scottish bridge seems to compel dogs to leap to their death.

But did the famous feminist and abolitionist ever really say those iconic four words?

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

Right next to departures—how convenient!

This church built atop a gas station promises to "equip you for the next stage in your life’s journey."