After the Casablanca Conference in 1943, WWII Allied leaders announced that Germany must “Surrender Unconditionally.” In mid-1945, British, French, Russian and American Zones of Military Occupation were established.
Because it was located 110 miles inside of the Russian Zone of Occupation, Berlin was subject to a special agreement between the victors. Four zones of occupation were also established there; this special agreement called for free and unlimited movement between the four zones of Berlin by its citizens and the occupying forces.
As the Cold War between the East and West deepened, Berlin’s perilous position meant that it was in constant danger of having the rail, water, and air supply and travel routes severed, which, of course, actually happened during the Berlin Blockade. Between June 24, 1948, and May 12, 1949, an Allied airlift supplied everything that the two million West Berliners needed. At Tempelhof Airfield in the American Zone, an aircraft landed every 45 seconds carrying everything from coal to spam!
By 1960, when the story of The Berlin Tunnel—A Cold War Thriller begins, hundreds of thousands of East German citizens were escaping to the West through East Berlin each year. Once there, freedom was only a short subway ride away. They could only take one small suitcase with them, but they could live free. Movement of peoples between the East and West was controlled by the 81 checkpoints in a continuous barrier that surrounded West Berlin. The control of peoples movement was necessarily loose because hundreds of thousands passed between those barriers daily, most on the extensive subway system.
Because the infrastructure there was already overloaded, the East Germans that fled to West Berlin were not allowed to stay there. Every day, five to seven airplane-loads of former East German citizens were flown to West Germany. Most of those who fled were the young and educated; they could easily get a good job in the West. So many dentists had immigrated that by one count, only 334 dentists were left to serve nineteen million people.
East Germany was rapidly becoming a nation of the old and infirmed. The communist leaders knew that something had to be done. With Russian dictator Khrushchev’s approval, the East Germans closed the Berlin Wall at midnight on August 13, 1961. This barrier was only a wall in central Berlin, most of the rest consisted of chain link fences with a barbed wire top. Soon only thirteen checkpoints including the famous Checkpoint Charlie remained. For 28 years, friends and family physically only separated by a few feet were denied the fundamental human right of free association.