Imagine, if you can, waking up some morning to find a wall running down the center of the main street of your town, cutting your city in half. No one may cross from one side to the other, regardless of family situations, jobs, or schooling. To do so, would be to risk death. Furthermore, imagine that on one side of the wall people are permitted to do all the normal things that free people expect to do, and they may go and come at will. But on the other side many freedoms are taken away from the people.
This is what happened in the city of Berlin, once the proud capital of Germany, in 1961. The Berlin Wall was erected by the Communist government East Germany to keep East German citizens from escaping to the repression that became known as the Wall of Shame. Hundreds of people died trying to cross it. Thousands of lives were disrupted.

Situation after WW II

After WWII Berlin was divided into 4 sectors. The largest sector was the Russian sector. The western sectors belonged to Great Britain, France, and USA. After Nazi Germany surrendered, the 4 allied countries signed a treaty called “the Potsdam Agreement”, which determined the borders for Germany and Berlin.

The Attempt to Strangle Berlin

On June 21, the three Western powers decided to unite their zones into a single unit, with the goal of forming a West German state the following year. In addition, they announced a decision to issue a new West German currency.
Unable to get the Soviets to agree to a single occupation currency for the entire city, and unwilling to use a Soviet-issued currency, the Western powers announced that West German marks would be used in Berlin. Angered, the Soviets introduced a currency of their own into the city on June 23. The next day, they began to impose a blockade on Berlin.
Demanding that all Western troops leave the city, the Soviets shut off all land access to the western sectors. Roads and railways were blocked. Barges could no longer use the canals, and the power lines that carried electricity from East Berlin to the western sectors were turned off. The Soviets were trying to bring Berlin to its knees. West Berlin was an island in communist East Germany. Cut off from all over the world, the western sectors could probably have kept going for no more than six weeks.