Moscow's imposing monument to the Space Age.

A cylinder monument with a spectacular vista commemorates a friendship that some say never existed.

A crumbling bakery where forced laborers from the nearby concentration camp toiled to feed their fellow prisoners and Nazi soldiers.

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

Cold war icon and onetime "hole" in the iron curtain.

Berlin's old airport.

What started as a tongue-in-cheek shrine is now a full-blown museum celebrating "The Hoff" and his longtime love affair with Berlin.

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

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

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

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

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

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

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

An eerie, derelict amusement park in Berlin.

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

Berry Gordy Jr.'s old home was the original headquarters of Motown Record Corporation.

An architect's childhood fantasy treehouse made real.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Opulent downtown movie theater now houses cars as an indoor parking garage.

The collection of ceremonial and cultural objects spans many countries and hundreds of years.