During which war was the Berlin Wall taken down?
And the answer: The Cold War.
A rivalry between the United States, the Soviet Union, and their respective allies, the Cold War began in the aftermath of World War II, and effectively ended when the Soviet Union dissolved in 1991. The Berlin Wall was a powerful symbol of the physical and political divisions of the Cold War, and was dismantled in 1989.
At the close of World War II, a new world order was put in place. Joseph Stalin took hold of Eastern Europe, spreading communism as a buffer from the USSR and the West. This buffer was later known as the Iron Curtain, which separated the communist Soviet Union from the Democratic-leaning Western world. With the establishment of the North Atlantic Treaty Organization (NATO) and the Truman Doctrine (which essentially declared the Soviet Union untrustworthy), tensions rose to the heights which typically indicate the beginning of the Cold War.
In response to the rising of the Iron Curtain, the United States began sending economic aid to Western European countries devastated by World War II. Meanwhile, the Eastern Bloc was barred from such aid, and lived in intense famine and destitution. Quickly, the Cold War turned to an economic battle between capitalism and communism.
If the Western nations developed faster and better than the East, it would represent a defeat for Stalin, so the Soviet leader developed his own economic recovery plan in response. Most pertinently, Stalin developed a plan for more complete control over the Eastern bloc called Cominform, which quickly came to a head in Berlin. Since Berlin was just 100 miles from the edge of the Eastern bloc, and had already been divided into West and East Berlin by the allies, Stalin realized he needed to set up a proper blockade between the city if he were to control power. Thus, the Berlin Wall was constructed.
The Berlin Wall stood until the Soviet Union began to collapse in 1989, which marked the beginning of the end of the Cold War (finally coming to a close in 1991). Learn more about the divide between the West and Eastern world during the Cold War here.