Inside a former cabaret, seven floors of erotic art.

The site of the first medieval crusade that pitted Christians against Christians.

Statue of death tucked in the University of Medicine courtyard.

The largest underground church in Europe.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

Bits of architecture from a town destroyed in World War I now decorate this hotel garden.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

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

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

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

A chapel on a volcanic core, marking the end of a successful journey.

A French valley with forests so lush it was nicknamed "the Small Amazonia of the Pyrenees."

France's highest manned weather station is the only one still inhabited by meteorologists.

This army of concretions is an unexplained geological phenomenon unlike anything else in the world.

This French "sea of rocks" is packed with stunning rock formations and its own medieval castle.

The castle where the Marquis de Sade lived out his darkest fantasies.

The music is over at the Ballhaus Riviera Ballroom, but the ballroom remains in haunting disrepair.

Dancing skeletal figures pay homage to a medieval mural destroyed during World War II.

A preserved Nazi labor camp now has a Holocaust museum on site and memorials to the thousands that died while imprisoned at the camp.

One man's personal kunstkammer, museum and shop.

Striking occult iconography on a medieval German church.

This ancient ruined monastery has been destroyed by fire so many times that it seems like God hates it.

Among the ostentatious rococo ornamentation of this church, an image of death cuts the life-thread.

This magnificent museum claims to house the cranium of a disciple and the skull of a pope.