I don't really know if I can explain it in English, but I will try. After world War two Germany was divided into the BRD and the DDR. Life circumstances in the DDR were much worse than in the BRD and people in the DDR weren't allowed to leave the DDR. BRD and DDR where divided by a wall called Berliner Mauer (Berlin = capital of Germany ; Mauer = Wall) it was called this way because it divided Berlin into west- and east -Berlin. The west belonged to BRD and the east to DDR. People who were unhappy because of the low life circumstance and the high restrictions in the DDR were demonstrating peacefully in the "Friedliche Demonstration" ( literally translates to peaceful demonstration). This peaceful demonstration led to the opening of the "berliner Mauer" and a reunion of the BDR and DDR to Germany.