What larger sector of Berlin was formed by joining the British French and U.S. sectors.?

The larger sector of Berlin formed by joining the British, French, and U.S. sectors is known as West Berlin. Established during the post-World War II division of Germany, West Berlin was a free city surrounded by East Germany and served as a focal point of Cold War tensions. It functioned as a separate political entity until the reunification of Germany in 1990.