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| Berlin is located in the middle of former German Democratic Republic (East Germany, or DDR). And the city was devided into two parts; East- and West-Berlin. Berlin-West was really an island surrounded by East Germany. In a sense of the cold war, it was in the enemy territory. |
| At the night of 13th August, 1961 East Germany started to close the borderline around West-Berlin. At first they stopped all the railway traffics like city trains(S-Bahn) and subways(U-Bahn) and at the same time put barbed wire as barriers on the border and later began to build a Wall with concrete blocks. |
| The Wall stood around West-Berlin, because it was a blocade to shut all the possibilities to reach the free side of the city. With these measures they intended to stop the flow of people from East-Berlin and East Germany into West-Berlin for freedom. |
| To make the blockade more efficient East Germany developed the system and devices, like "no-man's-land", electric alarms, watch towers, anti-vehicle trenches etc. |