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

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

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

Berlin's old airport.

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

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

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

A fascinating insight into daily life in the Eastern Bloc.

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

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

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

The most visited, and possibly most controversial, museum in Germany.

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

A former top secret nuclear fallout shelter now operates like a hotel stuck in the Cold War.

This abandoned airplane hanger is said to have once been a top secret launch facility.

Yugoslavia's biggest underground airport lies in ruins.

This huge metal monument is slowly being stripped to its concrete skeleton.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

This former estate of a fascist leader is now a burnt out ruin leading to a system of secret tunnels.

A miniature train-ride through Slovenia's largest cave system.

A relic from the Industrial Revolution got a second life as a contemporary performing arts space.

The walls of this medieval church are covered with perfectly preserved frescos, including a pristine example of the Dance of Death.

This abandoned Slovenian military barracks has become a punky-political art squat.

A whimsical bridge adorned with decorative dragons.