The former headquarters of East Germany’s Ministry of State Security (“MfS” or “Stasi”), a secret police and intelligence agency from 1950 to 1989, are partially open to the public. Stasi-Museum in Berlin-Lichtenberg is worth a visit for everyone interested in modern history. 

If you haven’t seen the movie “The lives of others”, you should (YouTube has a few snippets). A good primer for visiting the Stasi headquarters.

(* Headline from a speech by Erich Mielke on November 13, 1989 at People’s Chamber (“Volkskammer”) in Berlin / YouTube)