This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

A Jenga-style cylindrical tower of books that appears to go on forever.

Macabre astrological automaton clock dating to the late 1400s.

An ancient knight and a symbol of the city's freedom.

An homage to the medieval rulers of Bulgaria.

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

A tiny church on a man-made island in the Adriatic.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Dine amidst exotic plants at this former royal greenhouse.

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

Op-art architecture designed for happiness.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

Stockholm's narrowest alley is barely over two feet wide.

Stockholm's tiniest statue is of a small boy looking at the Moon.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

It houses the remains of a 17th-century version of the Titanic.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.