Visit The Stasi: Die Ausstellung Exhibit:
A small but extremely informative exhibition about the Stasi (the internal security force of the former German Democratic Republic, abolished in 1989.) on the ground floor of the Stasi documentation center. Ingenious spy equipment and rows of jarred 'bodily smells' taken from interrogation chairs illustrate the terrible extent of Stasi surveillance. The exhibition is in German, but if you call beforehand you can get a very knowledgeable guide in English.