Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

A historic Black graveyard hidden in the parking lot of one of America's largest malls.

A layered tribute to the work of mosaicist Isaiah Zagar.

A sculptural commentary on capitalism pokes up from the East River.

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

This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

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

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

Order scoops of pandan, lychee, and black sesame at this family-run institution.

A semi-scholarly approach to sex.

Elevated freight railway turned wildly successful urban park.

The first and only carousel with a lineup entirely of insects.

Every year model trains zip through a miniature New York City that's now 150 landmarks strong.

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.

Self-sufficient greenhouse floating on the Hudson River.

A beautiful, historic location open to the public.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

This once-grand marvel of engineering is now 41 miles of scenic hiking trail.

The real-life site of Ichabod Crane's infamous gourd attack.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

One of the earliest bowling lanes in the U.S. doubled as a sewing school during a time when women had little job opportunity.

This giant rock arrived at this quiet park thousands of years ago on the back of a massive glacier.