This abandoned caretaker's apartment is one of 13 left in the New York Public Library system.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

The site of the deadly Triangle Shirtwaist Factory Fire.

The most confusing clock in New York.

Empty, but not abandoned, this cavernous Brooklyn loading dock was once considered the largest individual building in the world.

An abandoned asylum once on the cutting edge of lobotomies may be reborn as a Christian college.

This old cement mine has been used as everything from a mushroom farm to a recording studio.

An odd, ancient window that may have once been part of a brutal prison is embedded in the side of New York's Police Plaza.

For over 80 years, Mayan ruins stood proudly in a most unlikely location.

This abandoned seaside fortress is now simply an imposing ruin being taken back by nature.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

This iconic tattoo shop has its own onsite museum with artifacts from the early history of modern body art.

A Frankenstein blend of science and art allows one tree to produce 40 different types of stone fruit.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

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

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

What was once a trend-setting, phrase-coining icon of architectural splendor is now a rotting, forgotten hulk.

Reclaimed by nature, the ruins of Doodletown, New York are remnants of a town consumed by a state park.

Hear the tales of New York's most notorious criminals.

The oldest living tree in Manhattan comes shrouded in sinister legend.

This hidden library of physiological ephemera contains centuries worth of knowledge on the vim and viscera of the human body.

Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

A long abandoned hospital building on the outskirts of NYC.

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.