A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

Hundreds of hidden passageways weave through the old quarters of Lyon.

The curious underground history of keeping Paris clean.

A unrivaled and rather horrifying collection of wax dermatological models.

Indents in the pavement are all that remain from a grisly death machine in Paris.

Stroll through retro Paris while shopping for old postcards and discarded doll heads.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

The middle finger of modernity.

Venice's "Island of the Mad."

This community on a small Venetian island has taken to painting their houses in bright neon hues.

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

Stalactites and stalagmites in a beautifully lit cave.

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

A 16th-century horror show built in a lovely Italian garden.

A miniature desert appears out of nowhere on the lush isle of Lemnos, like something out of a Greek myth.

This little Greek plateau is home to thousands of rustic, white-sailed windmills.

This secret coastal village is studded with pastel-colored houses all piled on top of one another.

The secular incarnation of a religious meditation.

The rocky remains of an ancient Greek forest.