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

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

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

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

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

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

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

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

Longest fortress system anywhere in Europe.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

Humble beginnings for one of the world's most famous scientists.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

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