In 1946, one year after the end of the World War II the Soviet Military administration begun to safeguard the demarcation lines of the Soviet sectors to the West.
  
Traveling between all sectors of Germany was restricted and an "Interzonenpass" (Inter-zone passport) was required to travel from one sector to another. The Interzonenpass was 30 days valid and travellers had to apply for that pass at the authorities which could refuse the application. Crossing the border between East and West Germany without permission was possible but became more and more dangerous.
Thousands of East German citizen had escaped to the West over the borders between East and West Germany, East Germany and Berlin and within Berlin.
  
On May 26, 1952 the East German government decided to close the border and to build up a frontier area between East and West Germany and between West Berlin and East Germany.
After May 26, 1952 there was only one quite safe way to escape to the West: Berlin.
Although many border crossing points were closed in Berlin and controls at the border happened, it was quite easy to leave the Eastern sector of Berlin to the Western sector. Many East German citizen went to Berlin, bought a S-Bahn (suburban train) or U-Bahn (subway) ticket  and left East Berlin.
  
On August 13, 1961 the East German government decided to close the 'last gap' in the border to West Berlin and the Berlin Wall was build up.
East German citizen were not allowed to leave the country without permission.
However, during the first days many people could escape through the border but day by day it became more dangerous.
At the beginning people tried to climb over the Wall or the fences, they jumped out of the houses which were in the border area or tunnels were build to escape. During the first days several people lost their live or were killed by the Eastern border guard .
Günter Litwin was the first victim who was shot down by East German border guard in Berlin on August 24, 1961.
  
171 people were killed or died attempting to escape at the Berlin Wall between August 13, 1961 and November 9, 1989.