This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Unlock the secrets of the conjuring arts.

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

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

In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

This innocent-looking townhome is actually a subway exit.

Become a prohibition rebel.

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

A WWI fighter plane and turn-of-the-century penny candy shop are among the unexpected features of this Financial District building.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

A historic 1890s architectural masterpiece with an iconic clock tower that, once open to the public, now faces an uncertain future.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Visit the site of a subway powered by nothing more than air--and lots of it.

Deep under Manhattan is the largest construction project in city history. So far, the project has taken the lives of 23 workers, or "a man a mile."