Baroque celebration of the end of the Great Plague of Vienna.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

Macabre museum devoted to historical Viennese murders.

An underground city of salt.

A church of bones, decorated with 40,000 human skeletons.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

Macabre astrological automaton clock dating to the late 1400s.

Looming communist pillar with a Czech twist.

Cold war icon and onetime "hole" in the iron curtain.

Terrifying derelict military hospital once housed a recuperating Hitler.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

An eerie, derelict amusement park in Berlin.

An old department store turned Nazi prison turned artist commune.

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

Inside a former cabaret, seven floors of erotic art.

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

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

The celebrated eyesore created by starry-eyed sweethearts.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.