On November 9th, 1989 East Germany opened the border and the symbol of Iron Curtain, the Berlin Wall lost its significance. The concrete wall that surrounded West Berlin was mostly destroyed during next year. Germany was reunited on October 3rd, 1990.
With the closure of the inner German border in 1952, West Berlin became the main route by which East German citizens left for the West. By 1961 approximately 20% of total population of the GDR (German Democratic Republic) migrated to the West. To prevent further mass emigration, in August 1961 the East German government began construction of the wall around the whole West Berlin.
Initially installed barbed wire fence was soon replaced by the concrete structure. The final wall, completed in 1980 consisted of thousands of reinforced concrete sections. In fact, East Germans erected two parallel concrete walls with no man's land in between. Over time they walled up all the windows facing west, in other added bars, erected watchtowers, built bunkers, barricades, signal fences, anti-vehicle trenches, and other obstacles.