A spherical "micro-nation" in the heart of Vienna.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

An old department store turned Nazi prison turned artist commune.

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

The most visited, and possibly most controversial, museum in Germany.

This abandoned Slovenian military barracks has become a punky-political art squat.

Inspired by the Rialto Bridge in Venice, these three clustered bridges were just one part of a Slovenian architect’s grand vision.

Some of the best-preserved specimens of the monumental medieval tombstones found throughout Bosnia and Herzegovina.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

Oriental bazaar in the heart of Sarajevo.

This historic cemetery was inaccessible for several years due to dozens of land mines.

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

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

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

This doorless 20th-century elevator doesn't stop or slow down.

Macabre astrological automaton clock dating to the late 1400s.

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

A mocking tribute to the past and modern leadership of Prague.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

The gardens and chambers of this Moorish citadel conjure memories of the Alhambra.

This Moorish fortress has guarded Málaga from the slopes of Gibralfaro hill for nearly a thousand years.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.