This modest marker near Notre Dame identifies the very center of Paris.

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

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

Abandoned railway line circling the city of Paris.

Notorious artist squat renovated into legal studios.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The highest peak in mainland Spain is said to be the final resting place of a Muslim king.

This abandoned, turn-of-the-century astronomy hub is now the subject of more photographs than it ever took.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

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

The giant skeleton sculpture is surprisingly well-traveled.

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

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

Before there were doorbells this bronze ear was installed for visitors to announce their arrival.

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

The odd depiction of the Virgin Mary and baby Jesus is rooted in the Catholic Church's eradication of Catharism.

One of the world’s smallest bars, just 13 square feet, is brimming with speakeasy flair.

Da Vinci's equestrian statue, 500 years in the making.

Remnants of cone-shaped fascist bomb shelters in Milan.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

What once sat in the world’s spotlight is today a largely disused ghost complex.