The underground sanctuary of a mysterious ancient cult.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

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

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

This former Roman Catholic Church still contains the embalmed hearts and organs of 22 popes.

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

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

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

The oldest stone house in Paris was built by its most famous alchemist.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

Beggars were miraculously "cured" of their fake ailments when they returned home to this 17th century Paris slum each night.

France's national museum of scientific and industrial instruments.

Where the high court feasted, frolicked, and high courtesans put their royal lovers' diamonds to the test.

Dedicated to the art of hunting, with juxtapositions of contemporary art.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.