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

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

Mysterious 500-year-old tapestries depict a unicorn hunt.

A good place to research the Freemasons, esoterica, occultism, and hermeticism.

The most confusing clock in New York.

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

A posh members-only club with a literally dramatic history.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

The first American department store, and home to the largest operating musical instrument in the world.

Golden and naked, the figure that was once the highest point in New York is all that remains of the second Madison Square Garden.

Dr Barnes' $25 billion private collection of art and arboretum.

A museum within a museum, devoted to history's most questionable medical devices.

A wall of chewing gum moonlights as collective art.

137 graves holding New England's earliest residents.

The headquarters of the famous Yale society.

An archival collection of over 2,200 case studies which includes human brain specimens and tumor specimens.

A vast collection of rare books, manuscripts & extraordinary objects illustrating the history of medicine.

Final resting place of one of the classic authors of horror literature.

Books bound in human skin and H. P. Lovecraft's letters are among a few of the treasures this library has to offer.

The vaguely man-shaped root that ate the body of the founder of Rhode Island.

An architectural statement of artistic intent smack in the middle of Providence, Rhode Island's Colonial uniformity.