Nikola Tesla's former home contains an homage hidden from plain sight.

The former hotel where Tesla invented the radio.

A vibrant, 100-foot-tall mural dedicated to Evelyn Nesbit, the tragic icon of the Gilded Age.

A semi-scholarly approach to sex.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

New York City's smallest piece of private property.

The first piece of public art dedicated to LGBT rights.

An aptly-named street near the birthplace of the modern LGBT rights movement.

The East Village tenement from the cover of Led Zeppelin’s 1975 album has a tea shop on the ground floor.

A Ukrainian church canteen doles out hearty fare in an East Village basement.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

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

The most confusing clock in New York.

Amid skyscrapers and traffic exists this unique aquatic ecosystem.

Salute the leader of the proletariat.

The Pickle Guys stand as a salt-stained holdout of the Lower East Side’s historic pushcart culture.

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

Home to a dizzying array of letterpress blocks with a rich history.

An accidentally hidden library containing the ephemeral history of New York.

A touching tribute to the "Queen of Soul."

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

Elevated freight railway turned wildly successful urban park.

The remains of a 19th century spring, and the site of an infamous unsolved murder.