A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

The only gallery in New York dedicated to olfactory art and the exploration of scent in art.

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

An odd, ancient window that may have once been part of a brutal prison is embedded in the side of New York's Police Plaza.

The façade of this building looks like a bingo board, but it's really a giant clock by a famed graphic designer.

Amid skyscrapers and traffic exists this unique aquatic ecosystem.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

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

Become a prohibition rebel.

New York City's only radical feminist independent bookstore.

The first museum in the United States dedicated entirely to posters.

Manhattan's Thirteenth Avenue was made on landfill then deliberately destroyed — apart from one small, obscure block.

A masterpiece of LGBT art has been restored in what may now be the most valuable restroom in America.

The artist and New York City icon lived, worked and died in this converted carriage house owned by another iconic artist, Andy Warhol.

A hidden "place of interment for gentlemen."

Historical figures from New York City's Catholic community reside in Midtown.

One kilometer of thick brass rod laid out before your eyes.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

New York City's smallest piece of private property.

The first piece of public art dedicated to LGBT rights.

Those belting out show tunes might not realize this piano bar marks the site where Thomas Paine died in 1809.

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

Built hundreds of years ago this downtown iron barrier once protected a much despised king.