Abandoned 19th century homes once occupied by naval officers, soon to be demolished.

This otherwise innocuous bodega was once the headquarters of the most feared assassin's guild in American history.

This 19th century brick building in Brooklyn stands out like the anachronistic landmark that it is.

Nondescript elevator doors open to reveal a stunning, surreal world.

A terrific purveyor of natural history objects and curios.

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

An unrealized dream to wirelessly electrify the entire Earth.

An abandoned Gold Coast-era mansion once intended for the exiled ruler of Albania, who never arrived.

A once crucial portion of the Long Island railroad still lays abandoned, waiting to be turned into an urban park.

A crumbling hospital from the 1850s on Roosevelt Island.

A museum devoted to bringing to light forgotten or neglected histories through exhibitions, education and public programming.

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

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