Harlequin costumes, signed scripts, and armor-wearing puppets.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

Architectural monsters are devouring this palace's every door and window.

The final resting place of the poets Shelley and Keats.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

An alchemist's "magic door" stands in the middle of a Roman park.

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

A tree that defies gravity grows in an ancient ruin.

Suffocating dogs was a common spectacle in the fumes of this noxious cave.

A surreal botanical garden with an even more surreal tour guide.

An unusual "skull with ears" sits in the crypt of this small church tucked away at the end of a narrow alley.

The remains of the left arm of the levitating philosopher-saint are kept in a 13th-century Neapolitan basilica.

An eerie, little-known Neapolitan museum filled with preserved human remains.

The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.