A formerly abandoned mental institute, now back in business.

Eclectic architecture in the woods of New York.

Series of storm drains connected to a dark urban legend.

The loneliest island in New York.

Legendary private island in the Bronx...devoid of rats.

Final resting place of two dozen New York City harbor ships.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

This was one of the first (and last) university-built and operated nuclear reactors.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

A tunnel once abandoned now thrives with graffiti art as an off-limits makeshift gallery.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.

Slyly buy a shake in the Parker Meridien lobby.

Rummage through this sunken ship, but leave your scuba gear at home.

NYC's legendary underground network for bovine transportation.

A crumbling hospital from the 1850s on Roosevelt Island.

A group dedicated to promoting boating, kayaking and environmental education programs.

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

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

One of the oldest Jewish cemeteries in the city, it is now overgrown with an urban forest.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

A prohibition era watering hole for the police.

Nondescript building owned by ExxonMobil working on siphoning Greenpoint Oil Spill out of the ground.

A 120-year oil leak slowly unleashes more gallons of oil than the Exxon/Mobil disaster.

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