Two very green residential towers cleaning the air in one of Europe's most polluted cities.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

The mark of the Devil's horns on a marble column in Milan.

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

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

The former home of France's controversial pop maestro is almost completely covered in ever-changing tributes and graffiti.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

The celebrated eyesore created by starry-eyed sweethearts.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

This bridge was constructed from the rubble of the infamous Bastille.

Egyptian Revival movie palace abandoned for decades and restored in 2013.

Paris' linguistic guide to the international language of, yes, love.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

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

A 12th-century Italian skirmish gets reenacted with 500,000 pounds of flying citrus.

The skulls and bones of thousands of soldiers line the walls of this small Italian chapel.

A massive mausoleum towers over the gravestones in a 19th-century Italian "model village."

These spartan apartments are provided to clergymen visiting Vatican City.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

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

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