What were the different sectors of Berlin?

After World War II, Berlin was divided into four sectors controlled by the Allied powers: the American, British, French, and Soviet sectors. The city was further divided in 1949 when East Berlin became the capital of East Germany (GDR) and West Berlin became a free city surrounded by East Germany. This division led to significant political, economic, and cultural differences between East and West Berlin until reunification in 1990. The sectors reflected broader geopolitical tensions during the Cold War.