A dark, dank room in subterranean Manhattan was the site of a ghastly murder.

Plot your trip through the city on the sidewalk.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

These ornate manhole covers were used for a now-forgotten purpose.

The former sign of this immortal music venue is just that--undying.

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

A bit of retro transportation flair preserved in the world's largest department store.

Church in Manhattan holds the bloody sock of Padre Pio, among with many other unusual relics.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

The former hotel where Tesla invented the radio.

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.

This slender three-story building has also had several famous residents.

The first piece of public art dedicated to LGBT rights.

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

After surviving abandonment, this powerful Latin American mural is alive again.

A strangely angled West Village home is the only monument to an explosion that took the lives of three American revolutionaries.

Red frames showcase remnants of one of New York's original subway stations.

The rough and tumble president's childhood home displays the shirt he was once shot in and the speech that saved him.

The one-time office of the architectural firm that ushered in the Gilded Age is now a Club Monaco.

A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

This monument to a veteran of the Mexican-American War is one of only two in Manhattan that serve as an actual mausoleum.

Cryptic messages embedded in the New York City sidewalk.

The walls and ceilings of the "Mexican Sistine Chapel" are almost completely covered with mural, sculpture, inscriptions and oil paintings.