The walls of Germany's Parliament still show the scars of the Red Army takeover in World War II.

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

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

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

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

Blitzkrieg bop your way through Berlin's Ramones Museum.

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

A fascinating insight into daily life in the Eastern Bloc.

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.

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

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

This classic restaurant features a gorgeous mirror-clad room.

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

A surreal museum of extraordinary industrial objects.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

An eerie, derelict amusement park in Berlin.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

A stately palace has been converted into the world's largest cannabis museum.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

The former 1920s mansion of a prominent Catalan developer was used as the Soviet Embassy during the Spanish Civil War, and there is still a bunker below the garden.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

A once-secret library of Freemason history in Catalonia.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.