This grisly effigy displays an early Christian martyr who was skinned alive and beheaded.

The city of Parma's cathedral is home to one of the greatest illusionistic frescoes of the Renaissance.

The narrowest street in Paris.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

The artist and his brother are buried in a landscape straight out of a van Gogh painting.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

This massive library holds what was once the largest book collection in the world.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

An unusual number plate signifies the building's saucy past.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

The headless bodies of more than 1,300 guillotined victims of the Reign of Terror are buried here in mass graves.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

France's most famous cemetery, with some of its most curious tombs.