An abandoned NSA listening post on Berlin's "Devil's Mountain."

Striking occult iconography on a medieval German church.

An icon of International Style architecture on the outskirts of Rotterdam.

For patriotic Russians, this memorial honoring the Soviet soldiers who died liberating Berlin in 1945 is the most sacred location outside of Russia.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

A collection of abandoned typographic signs from Berlin and beyond.

A wunderkammer of mysterious objects and stories.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

This artistic fountain display pays homage to this area's theatrical history.

This historical Netherlands fortress still bears the marks of its single siege.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

These lights mark the area of Rotterdam that was bombed and burned in 1940.

This unique sculpture is often overlooked by pedestrians.

A beautifully eclectic mix of architectural styles.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

Cat art as far as the eye can see.

The former Field Marshall and Minister of War to the Russian Imperial Army.

This unique sculpture proved invaluable when it saved a train from careening off the tracks.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

This Dutch art piece became a Russian icon.

This Buddhist monastery once housed an image of Buddha containing a 19-carat diamond.

This building featuring Brutalist architecture has a rich media production history.

A Swedish phone box converted into an informal village library.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.