Short answers, pulled from the story.
West Berlin was the western part of Berlin, comprising the American, British, and French occupation sectors established in 1945. It was a political enclave because it was entirely surrounded by East Germany and East Berlin, located about 100 miles east and north of the inner German border, and accessible from West Germany only by narrow road and rail corridors.
The Berlin Wall was built on the 13th of August 1961, physically sealing the 46-kilometre sectoral border between East and West Berlin. It stood until the 9th of November 1989, when East Germany opened the border for East Germans and East Berliners.
West Berliners were not eligible to vote directly in West German federal elections because of West Berlin's ambiguous legal status as occupied territory. Instead, the city's House of Representatives chose 22 non-voting delegates to attend the Bundestag in Bonn, and the city Senate sent four non-voting delegates to the Bundesrat.
Male residents of West Berlin were exempt from the Federal Republic's compulsory military service because West Berlin was under Allied military occupation and not fully subject to West German federal law. This exemption made the city a popular destination for young West Germans seeking to avoid conscription, contributing to a flourishing counterculture.
During the Berlin Blockade, which ran from the 24th of June 1948 to the 12th of May 1949, the Western Allies used their three guaranteed air corridors to fly in food and essential goods through the Berlin Airlift. The airlift continued until the 30th of September 1949 to build up a strategic reserve called the Senate Reserve.
East and West Berlin formally reunited on the 3rd of October 1990, the day Germany was officially reunified. The combined city of Berlin joined the enlarged Federal Republic of Germany as a city-state, and Eberhard Diepgen, a former mayor of West Berlin, became the first elected mayor of a reunited Berlin after city-wide elections in December 1990.