Berlin 's past as an espionage hotspot has left the city with numerous spying - linked attractions . The Stasi Museum features relics of East Berlin 's obsession with killing its own citizens . In its heyday , the Ministry of State Security , or Stasi , was the all-powerful shadow government of the communist German Democratic Republic ( GDR ) . Other attractions include a tunnel used to tap into telephone lines , and an antenna farm .
Berlin 's past as an espionage hotspot has left the city with numerous spying - linked attractions . The Stasi Museum features relics of East Berlin 's obsession with killing its own citizens . Other attractions include a tunnel used to tap into telephone lines , and an antenna farm .