A hidden architectural treasure in New York's Brooklyn.

Try not to get slimed in Tribeca.

Revolutionary War casualties fill the only 17th century structure remaining in Manhattan.

An unassuming secret door once led to a legendary watering hole.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

100 massive sculptures in the Hudson River Valley.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

A grand New York post office that is home to mailman Santas, scraps of postal history, and a pneumatic mail system.

Cheap pizza and all of your naughty bedroom needs housed in a stunning example of Art Nouveau architecture.

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

The home of one of America's most beloved fictional characters has become a real world landmark.

This humble historic facade hides a history of boozing and the gentlemanly sport of rat-fighting.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

This New York holdover was built to provide housing for shopgirls and still does not allow men above the lobby.

This small-town pizzeria won the Hollywood lottery.

How did the right arm of a 13th-century English bishop wind up in a Connecticut church?

On the top floor of an upscale department store stands a lavish restaurant housed in a replica of a luxury French dining car.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

There are owls with glowing eyes in Herald Square.

These mouldering mansion ruins remember a time when the Catskills were nothing but luxury.

The home of one of America's most wealthy industrialists is now a historic site that remembers a more decadent time in the country's history.

A once grand hotel is being retaken by the wilderness it once capitalized on.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.