An eerie, derelict amusement park in Berlin.

This conical hill was built as a testing ground for an engineer known as the Glider King.

A statue of an astronomer gazes at the sky as a tribute to Caroline Herschel.

This platform is now a memorial dedicated to those who were deported during the Holocaust.

A unique Holocaust memorial tells the personal stories of the Jewish residents exiled from greater Berlin.

Started as a kitchen garden, now the second largest botanical garden in the world.

Home to 10,000 medical specimens including the remains of Rudolf Virchow's extensive collection of pathological specimens.

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.

One of the largest legal spray spots in Hamburg.

A wunderkammer of exoticism immortalized by Tom Waits.

Hidden in plain sight on a gable between two towers on the roof of shipping firm F. Laeisz' headquarter in Hamburg sits an unexpected bronze sculpture.

The place where World War I began.

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

This ironic war memorial thumbs its nose at a campaign of inedible humanitarian aid food products.

This enormous abstract sculpture is part jungle gym, part elaborate noise-making machine.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

Inat Kuća, or "House of Spite," is more than just an oddly named restaurant.

A war-torn Olympic relic is being overtaken by graffiti and nature.

Oriental bazaar in the heart of Sarajevo.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

A monument on the pavement marks the spot where two cultures that shaped Sarajevo come together.

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

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

Built to celebrate the glory of a new queen, this forgotten monument has moved around Madrid three times, reflecting 200 years of political whims and city redevelopment.