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

This museum promotes informed contraception by documenting its often secret past.

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.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

Hans Christian Andersen for the postmodern world.

Copenhagen's celebrated theme park and gardens.

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

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

Medieval town turned hippie commune, once home to the secret foreskin of Jesus Christ.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

Five candy-colored villages on the Italian Riviera.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

An artful memorial to 4,000 fateful oranges.

The largest catacomb system in the world.

This attraction was abandoned after the Chernobyl disaster.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

A 12th-century fortress containing some of Berlin's oldest buildings.

A striking 12th-century-style castle built on the edge of a cliff.

A fascinating insight into daily life in the Eastern Bloc.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.