The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

The "Prussian Versailles" that is as glorious today as when it was built.

Germany's Glienicke Bridge has a shady history of clandestine meetings, espionage, and spycraft.

This TV tower once secretly housed a GDR intelligence team.

The music is over at the Ballhaus Riviera Ballroom, but the ballroom remains in haunting disrepair.

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

Gardens representing parts of Asia, Europe, and the Mid East are tucked away among the Soviet-style buildings in East Berlin.

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

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

A traditional U-Bahn station in Berlin gets a string of rather untraditional benches.

A restaurant and observation deck built in a unique broadcasting antenna.

The final resting place of many of Germany's most famous communists.

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

A century-old shot ball factory tower is open to the public once a year.

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

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

A portable, wooden replica (minus the hyphen) of Hamburg’s iconic crooked coffee shop.

Floating swimming pool within a moored vessel.

Super-heavy Nazi architectural experiment.

Berlin's old airport.

Where once there was a train station bathroom, there is now this German burger joint.

Metro station with a claim to rock n' roll fame.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Named after a militant urban guerilla, this famous former squat is a graffiti-covered stronghold of leftist culture.