Since World War II, the old German capital of Berlin was divided into four sectors. Each sector was occupied by a different nation that fought against Germany in World War II. The Soviet Union had influence over not just the eastern part of Berlin, but also East Germany, which was ruled by its own Communist government. The heavily-guarded Berlin Wall split the Soviet-occupied part of Berlin from the sectors occupied by the United States and its allies. Hundreds were shot trying to leave East Germany for the west.

On June 26th, 1963, Kennedy gave a speech on the western side of the Berlin Wall praising freedom, which represented a high point for his global popularity.

Since the United States used nuclear bombs against Japan in World War II, both the United States and the Soviet Union had tested new nuclear bombs. The tests caused radioactive fallout, which could contaminate food and cities.

By October 1963, Kennedy and the Soviet Union negotiated the Limited Nuclear Test Ban Treaty. This put an international ban on atmospheric testing of nuclear weapons. Kennedy “considered it the most significant achievement of his presidency” (33).