The encased skull that is widely believed to belong to St. John the Baptist.

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

An isolated 17th-century chapel on a remarkable site once dedicated to Celtic sun worship.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

Hundreds of secret cabinets built into the walls of legendary poisoner's private work room.

An ancient monastery, a locked room, and a mysterious book heist.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

There has been an astronomical clock on this spot since the 14th century.

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

Saintly bones pressed into a wax effigy of a Catholic superstar.

The famous winding walk at Chartres is surrounded in mystery and myth.

This little-known relic crypt holds stolen parts of a Roman Empress.

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

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

Science fiction's grandfather has a fittingly marvelous tomb.

A medieval military street hidden beneath a charming French fishing village.

A Gothic cathedral created from volcanic rocks.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

The largest underground church in Europe.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

This museum in a Paris apartment gives a unique look at the iconic French singer's life.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.