The former hotel where Tesla invented the radio.

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."

Unlock the secrets of the conjuring arts.

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

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

From scholastic to sepulchral - now under reconstruction.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

Try not to get slimed in Tribeca.

Tucked in the back of this amazing antique store is an important piece of medical history.

A terrific purveyor of natural history objects and curios.

Macbeth's infamous "Great Birnam Wood."

A 200-year-old collection of oddities and medical paraphernalia.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

A site of pagan worship which still attracts people looking for fairies.

This tiny little cave was said to have been a refuge for a saint with a glowing arm.

Ruined castle with subterranean vaulted Goblin Ha' or "Goblin Hall."

This series of Scottish caves has no clear purpose other than baffling historians.

A book bound in the skin of an infamous criminal, along with countless other specimens.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

This landmark church concealed a crypt packed with bones that was discovered thanks to the London Blitz.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

The final resting place to 300 Victorian-era pets hides inside the city park.