MfS

The MfS (Ministerium für Staatssicherheit or Stasi) was the official state security service of the German Democratic Republic (also known as East Germany). It's main task was to spy on its own citizens and to fight any and all forms of opposition to the State. Now, it's headquarters in Berlin are a remarkably cheerful museum providing a glimpse into the inner working of one of the most feared and repressive secret police agencies in the world.