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.

Bursting forth from a historic German neighborhood, these day-glo palaces are now a bright fixture in the town.

This German monument honors the so-called "Prince of Mathematicians."

Mummies preserved naturally for seven centuries.

A Turkish ghost town abandoned in a population exchange with Greece.